Human Body Systems Part II -

Human Body Systems Part II -

Y D O B N A MS M N E O U H YST II A R S S RTS A L A P LY S A TABLE OF CONTENTS Section 1 The Endocrine System Endocrine System Introduction and Function Homeostasis 3 Negative Feedback Mechanism 4

Endocrine Glands of the Human Body Diabetes Types I and II Hypothyroidism 5-6 7-8 9-10 Endocrine System Reference Pages 11-12 1-2 TABLE OF CONTENTS Section 2 The Reproductive System and Development Introduction and Functions of the Reproductive System Sexual and Asexual Reproduction in Animals Spermatogenesis Oogenesis 15

16-17 18-19 Menstrual Cycle and Estrous Cycle 20 Menstrual Cycle in Humans and Primates Development 24 Ovarian Cysts 25-26 Prostate Gland Enlargement 21-23 27-28 Reproductive System Reference Pages 29-30

13-14 TABLE OF CONTENTS Section 3 The Nervous System Introduction and Function of the Nervous System Central and Peripheral Nervous System Simple Reflex Arc 34-35 Parts of the Brain and Functions The Neuron 33 36-40 41 Nerve Impulses 42-46 Role of Neurotransmitters 47

Parkinsons Disease 48-49 Migraine Headaches 50-51 Nervous System Reference Pages 52-53 31-32 TABLE OF CONTENTS Section 4 The Senses System Introduction and Types of Sensory Receptors The Eye 60 Rhodopsin and Cell Signaling Senses System Reference Page 61 62

54-59 TABLE OF CONTENTS Section 5 The Muscular System Introduction and Function of the Muscular System Types of Muscle Tissue The Sarcomere 65-68 69 The Sliding Filament Model 70-74 Duchenne Muscular Dystrophy Chronic Compartment Syndrome Muscular System Reference Pages 75-76 77-78 79-80 63-64 TABLE OF CONTENTS

Section 6 The Skeletal System Introduction and Function of the Skeletal System 81-82 Roles of Bones, Ligaments, Muscles, and Tendons in Movement Types of Skeletons 84 The Long Bone Rickets Osteoporosis 85 86-87 88-89 Skeletal System Reference Pages 90-91 83 E TH

E D N C O I R E N S Y S M E T 1 Endocrine System

FUNCTION OF THE ENDOCRINE SYSTEM Regulates metabolic processes, growth of the body and sexual development The endocrine system consists of hormones and glands Hormones secreted by the endocrine system influence the body to react according to: Changes in the balance of fluids and minerals in blood Stress Infection Organs of the endocrine system: Pineal gland Pituitary gland Parathyroid gland Thyroid gland Adrenal glands Pancreas Ovaries (in females) Testes (in males) Thymus 2

HOMEOSTASIS Homeostasis is the ability of an organism to maintain stable internal conditions by regulating its physiological processes Endocrine System The endocrine system helps maintain homeostasis by releasing hormones The endocrine system works by using a feedback system when the chemical level of a certain substance is abnormally high or low, the endocrine system secretes hormones to reach an internal equilibrium

3 Endocrine NEGATIVE FEEDBACK MECHANISM System The negative feedback mechanism is one of the most important features of the endocrine system Means that the a gland within the endocrine system will stop producing a hormone to avoid a hormone imbalance Example: The hypothalammus secretes TRH, which causes the pituitary gland to release TSH TSH causes the thyroid gland to secrete T4 (thyroid hormone) When thyroid hormone accumulates in the blood, it causes the hypothalamus and pituitary gland to slow the secretion of TRH and TSH. The negative feedback mechanism is also used by the ovaries, testes and adrenal glands 4 Endocrine

System 5 THE ENDOCRINE GLANDS AND HORMONES Endocrine System Gland Hormone & Action of Hormone Pineal gland Melatonin communicates information about environmental lighting to various parts of the body Pituitary gland Growth hormone promotes growth in children. In adults, helps maintain muscle and bone mass Parathyroid gland

Parathyroid hormone regulates calcium and phosphorus concentration in extracellular fluid Thyroid gland Thyroxine controls metabolism Adrenal glands Norepinephrine activates fight or flight mechanism. Greater muscle strength and enhanced senses Pancreas Insulin takes glucose out of the blood, maintains blood glucose levels Ovaries (females) Estrogen development of female sexual characteristics Testes (males) Testosterone development of male sexual characteristics Thymus Thymopoietin regulates immune function

6 DIABETES TYPES I AND II Endocrine System Marked by persistent or recurring elevated levels of blood sugar because of the absence of blood sugar or the inability of the body cells to react to insulin Can be treated with changes in diet, exercise, or the injection of insulin NOT curable Can lead to coma, heart disease, kidney failure, blindness, amputation Diabetes Type I shortens life expectancy by about 15 years

Diabetes type II shortens life expectancy by about 5-10 years 7 Endocrine System DIABETES TYPE I TYPE II juvenile onset diabetes usually begins in childhood or adolescence Body destroys the pancreatic cells that create insulin, the hormone that removes glucose from the blood High blood sugar damages body tissues Treated with insulin

injections About 95% of diabetes cases in America are Type II slow onset diabetes appears over the course of several years The body produces insulin, but the cells dont respond to it correctly Treated with a change in diet and exercise habits, and weight loss Affects the sedentary, obese, and elderly Can usually be controlled without insulin therapy 8 HYPOTHYROIDISM a condition in which the thyroid gland is underactive doesnt produce enough of certain important hormones

Upsets the normal balance of chemical reactions in the body More likely in women especially over the age of 50 Endocrine System Signs and Symptoms: Fatigue and sluggishness Increased sensitivity to cold Constipation Pale, dry skin A puffy face Hoarse voice An elevated blood cholesterol level Unexplained weight gain Muscle aches, tenderness and stiffness Pain, stiffness or swelling in your joints Muscle weakness Heavier than normal menstrual periods Brittle fingernails and hair

Depression 9 Endocrine System HYPOTHYROIDISM Prevalence: It is estimated that 20 million Americans have hypothyroidis m Treatment: Synthetic thyroid hormone T4 replacement hormone Taken in the

morning and 30 minutes before eating 1 Endocrine System ENDOCRINE SYSTEM REFERENCE PAGE Holes Human Anatomy & Physiology Textbook (Chapter 13 Endocrine System) pineal.html 1 REFERENCE PAGE (CONTINUED) Endocrine System Pictures: tabid/2242/Default.aspx categoryID=R21&priority=25&categoryName=Insulin%20Pens %20and%20Pen%20Needles&categoryImgPath=/ecat/images/f95/ insulin-pen.jpg&sortByField=Product %20Number&viewPageNum=0 1 E E V M I P T O C L

U E D V O E R D P E & R M E E H T YST S T N 1 THE REPRODUCTIVE SYSTEM Reproductive System Function: The reproductive system functions in procreation and survival of species

Produce egg and sperm cells, transport and sustain cells Develop and nurture offspring (females) 1 Reproductive System SEXUAL AND ASEXUAL REPRODUCTION SEXUAL REPRODUCTION ASEXUAL REPRODUCTION The haploid gametes of two individuals (male and female) join to create a diploid organism (fertilization) The offspring receives genes from each parent One individual produces offspring that are

genetically identical to itself Offspring varies genetically from its parents Produced by mitosis Examples: Budding an offspring grows out of the body of the parent (seen in hydras) Gemmules - a parent releases a specialized mass of cells that can develop into offspring (seen in sponges) Fragmentation - the body of the parent breaks into distinct pieces, each of which can produce an offspring (seen in planaria) 1 SPERMATOGENESIS Reproductive

System The process of sperm cell formation Begins with spermatogenic cells, which give rise to sperm cells (spermatozoa) Undifferentiated cells called spermatogonia have 46 chromosomes. Hormones stimulate the spermatogonia to become active. Some of the cells undergo mitosis. Each cell division gives rise to two new cells One is type A, maintains the supply of undifferentiated cells One is type B, enlarges to become a primary spermatocyte At puberty, new spermatogonia form. Testosterone secretion increases, and the primary spermatocytes begin to reproduce by meiosis Each primary spermatocyte divides to form two secondary spermatocytes. The secondary spermatocytes then divide to form two spermatids, which mature into sperm cells

Product is four spermatids with 23 chromosomes each 1 Reproductive System 1 OOGENESIS Reproductive System The process of egg cell formation Early in development, primary oocytes begin to undergo meiosis. The process soon stops and does not continue until puberty At puberty, some primary oocytes are stimulated to continue mitosis

The resulting cells have 23 chromosomes in their nuclei Unlike a primary spermatocyte, when a primary oocyte divides, the cytoplasm is distributed unequally The secondary oocyte, one of the resulting cells, is large The other resulting cell, the first polar body, is very small The secondary oocyte represents a future egg cell that can be fertilized. If this happens, the oocyte divides unequally to produce a second polar body and a zygote that can become an embryo Polar bodies allow for the production of an egg cell with the massive amounts of cytoplasm and abundant organelles, but still with the right number of chromosomes Also provide food for the oocyte 1

Reproductive System 1 Reproductive System MENSTRUAL CYCLE VS. ESTROUS CYCLE MENSTRUAL CYCLE Involves menstruation, the shedding of the lining of the uterus accompanied by bleeding Takes place approximately once a month in women Starts during puberty and stops at menopause, also stops during pregnancy Has three phases Follicular before egg is released Ovulatory egg release Luteal after egg is released ESTROUS CYCLE

The period in the sexual cycle of female mammals (except higher primates including humans) during which they are in heat ready to accept a male and to mate One or more estrous periods may occur during the breeding season of a species Prior to ovulation the uterine lining thickens in preparation for holding the fertilized egg. When this reaches its peak, receptivity is the highest 2 THE MENSTRUAL CYCLE Reproductive System Menstrual cycle refers to the hormonal and reproductive tissue changes that occur in adult female humans and primates during their reproductive

years Menstrual cycles vary in length among different species a typical length of time is about 30 days A female can conceive only during a certain time, that is when her ovaries release an egg. This happens once during the menstrual cycle and is a part of the ovarian cycle. The menstrual cycle and ovarian cycle are tightly coordinated. Menstrual Cycle: The females body prepares for ovulation The lining of the uterus grows thicker to prepare for implantation If no implantation occurs, then the body breaks down the endometrium and discharges it through menstruation 2 THE MENSTRUAL CYCLE Reproductive

System The menstrual cycle is controlled by hormones Estrogen and progesterone, produced by the ovaries Estrogen and progesterone stimulate the formation of the endometrium lining in the uterus When the amounts of estrogen and progesterone decrease, the lining of the uterus breaks down and causes menstruation Follicle stimulating hormone (FSH) and lutenizing hormone (LH) produced by the pituitary gland FSH and LH control and stimulate the unripe eggs in the ovaries to ripen and to be released The hormones that regulate the menstrual cycle are controlled by negative feedback mechanisms 2 Reproductive NEGATIVE FEEDBACK MECHANISM System OF THE MENSTRUAL CYCLE

A negative feedback mechanism is a self-regulating system Increased output from the system inhibits future production by the system = the system controls how much of a hormone it makes by stopping production when the amount of the hormone gets too high The feedback mechanism: The hypothalamus releases a hormone (GnRH) that tells the pituitary gland to produce follicle stimulating hormone (FSH). In turn, FSH tells the ovaries to produce estrogen High levels of estrogen and progesterone inhibit the production of GnRH, so the pituitary gland will make less FSH, and the ovaries will make less estrogen 2 DEVELOPMENT Reproductive System After fertilization, cleavage takes place. Cleavage is characterized by a succession of rapid cell divisions during early embryonic development

Becomes a morula, a solid ball that consists of about sixteen cells The solid ball of cells hollows out and becomes a blastula, a hollow ball of cells The three germ layers begin to form, and at this time the embryo is called a gastrula. Gastrulation involes the formation of a 3-layered embryo stage with a blastopore beginning to form. Gastrulation progresses to organogenesis. During organogenesis, the organs begin the form from the primary germ layers germ layers are the primitive tissues from which all organs form The ectoderm, or outermost layer, forms the outer layer of the skin and the nervous system The mesoderm, or middle layer, forms the muscular system as well as the circulatory system

The endoderm, or innermost layer, forms the digestive and respiratory systems 2 Reproductive System OVARIAN CYSTS Ovarian cysts are fluid-filled sacs or pockets within or on the surface of an ovary Most ovarian cysts are harmless some, especially those that have ruptured, sometimes produce serious symptoms Symptoms: Menstrual irregularities Pelvic pain a constant dull ache, pain before the period begins or just before it ends, pain during

intercourse Pain or pressure on bowels during bowel movements Nausea, vomiting, or breast tenderness Frequent urination Difficulty emptying the bladder completely 2 OVARIAN CYSTS Prevalence: Ovarian cysts can be found in nearly all premonopausal women, though most of them are benign Found in up to 18% of postmenopausal women Reproductive System Treatment:

Most go away on their own May need to be removed by laparoscopy, in which a laparoscope is inserted through a small incision in the abdomen and the ovarian cyst is located and removed 2 Reproductive PROSTATE GLAND ENLARGEMENT System Prostate gland enlargement is a very common condition among aging men It is also called benign prostatic hyperplasia

(BPH) and prostatic hypertrophy When left untreated, a prostate gland enlargement can block the flow of urine out of the bladder and can cause bladder, urinary tract, or kidney problems The prostate gland closes off the urethra and may cause a change in shape of the urinary bladder Symptoms tend to worsen over time, and include: Weak urine stream Difficulty urinating Stopping and starting while

urinating Dribbling at the end of urination Frequent or urgent need to urinate Not being able to completely empty the bladder Urinary tract infection Reduced kidney function 2 Reproductive PROSTATE GLAND ENLARGEMENT System Prevalence: 50% of men ages 5160 years have BPH 90% of men over 80 years of age have BPH Only 25% of 55-yearold men and 50% of 75-year-old men will have bothersome symptoms related to prostatic enlargement Treatments: There are several effective treatments for

prostate gland enlargement. Treatments are based on symptoms, the size of the prostate, and other health problems that may be present. Common treatments include: Medication Lifestyle changes Surgery 2 Reproductive REPRODUCTIVE SYSTEM REFERENCE System PAGE Holes Human Anatomy & Physiology Textbook (Chapter 22 Reproductive System) Holes Human Anatomy & Physiology Testbook (Chapter 23

Pregnancy, Growth, and Development) the_menstrual_cycle.html DS00027

2 Reproductive REFERENCE PAGE (CONTINUED) System Pictures: 3 E TH N US O V R E T S Y

S M E 3 THE NERVOUS SYSTEM Nervous System Functions of the nervous system: Sends signals from one cell to other cells, or from one part of the body to the others Sensory neurons receive information from sensory receptors Neurons transfer and interpret impulses Motor neurons send appropriate impulses or instructions to muscles or glands Ultimately, the nervous system allows us to control our bodies by receiving and responding to stimuli 3 Nervous System TWO PARTS OF THE NERVOUS SYSTEM

CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM The CNS is made up of the brain and spinal cord Receives sensory information and controls the bodys responses. Includes all of the nerves outside of the brain and spinal cord Sensory division carries information from sensory cells to the CNS Motor division carries information from the CNS to organs, muscles, and glands (motor) Other divisions of the PNS include: Somatic Nervous System controls muscles under voluntary control (skeletal muscle) Autonomic Nervous System controls involuntary muscles (smooth and cardiac

muscle) Sympathetic activated when the body is under stress Parasympathetic controls normal, everyday activities 3 SIMPLE REFLEX ARC Nervous System Helps an organism avoid injury by providing a means for immediate withdrawal from dangerous stimuli Can process the rapid, protective response directly in the spinal cord without the need to wait for instructions from the brain Specialized cells in the skin detect a painful stimulus and relay the information to nerve cells in the spinal cord

The sensory fibers enter the spinal cord and synapse with interneurons within the spinal cord gray matter The interneurons synapse with motor neurons that control the skeletal muscles Stimulates muscles to contract and remove the body part from the painful stimulus 3 Nervous System 3

Nervous System 3 LOBES OF THE CEREBRUM Nervous System Frontal lobe associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal lobe associated with movement, orientation, recognition, perception of stimuli Occipital lobe associated with visual processing

Temporal lobe associated with perception and recognition of auditory stimuli, memory, and speech 3 DIENCEPHALON Nervous System The diencephalon is the general area in the middle of the brain above the brain stem. It includes the: Thalamus channels sensory impulses (except olfactory) into the cerebral cortex for interpretation and channels motor impulses from the cerebral cortex to the brain stem Hypothalamus links the nervous and endocrine systems by commanding the pituitary gland, so it indirectly regulates metabolic functions Limbic system an interconnected complex lying in various parts of the cerebral cortex, cerebrum, and diencephalon, that allows us to feel emotion 3 BRAIN STEM

Nervous System Connects the cerebrum to the spinal cord Midbrain contains visual and auditory tracking reflex centers Pons relay station for impulses going from the medulla oblongata to the cerebrum, and from the cerebrum to the cerebellum Medulla oblongata crosses over sensory and motor impulses, so the left cerebral hemisphere controls the right half of the body and the right cerebral hemisphere controls the left half of the body control center for vital functions (heart rate, blood pressure, and breathing) Reticular formation complex network scattered throughout the brain stem. Stimulates the cerebral cortex into wakefulness decreased activity leads to sleep, ceased activity leads to coma Filters 99% of all sensory input as unimportant 3 CEREBELLUM Nervous

System Integrates sensory information on body position and coordinates body movements Injury leads to loss of muscular coordination and balance 4 Nervous System 4 NERVE IMPULSES AND NEUROTRANSMITTERS Sensory neuron receives stimulus

Nervous System The nerve impulse passes from neuron to neuron (or to muscle cell or gland) at synapses A nerve impulse travels along the axon to the axon terminal When a nerve impulse reaches a synaptic knob, voltage-sensitive calcium channels open, and calcium diffuses into the cell from the extracellular fluid The increased calcium concentration inside the cell begins a series of events that cause the synaptic vesicles to fuse with the cell membrane Cell releases neurotransmitters by exocytosis 4

MEMBRANE POTENTIAL Nervous System A cell membrane is usually electrically charged, or polarized, so that the inside is negatively charged with respect to the outside creates a membrane potential Polarization is due to an unequal distribution of positive and negative ions on either side of the membrane Potassium ions (K+) are the major intracellular cations Sodium ions (Na+) are the major extracellular cations Distribution of K+ and Na+ is largely created by the sodiumpotassium pump, which actively transports sodium ions out of the cell and potassium ions into the cell

4 Nervous System A resting nerve cell is not being stimulated to send a nerve impulse RESTING POTENTIAL Under resting conditions, nongated channels determine the membrane permeability to sodium and potassium ions A resting cell membrane is only slightly permeable to K+ and Na+, but it is more permeable to K+ than it is to Na+ The resting potential has a value of -70 millivolts, meaning that there is a negative charge on the inside of the cell membrane The resting potential provides the energy for sending a nerve impulse down an axon

Once the resting potential is established, a few sodium ions and potassium ions continue to diffuse across the cell membrane. The negative membrane potential helps Na+ enter the cell but hinders K+ from leaving the cell 4 DEPOLARIZATION AND ACTION POTENTIAL Nervous System An environmental change affects the membrane potential by opening a gated ion channel If the membrane potential becomes more positive than the resting potential, the membrane is depolarized The greater the stimulus, the greater the depolarization If neurons are sufficiently depolarized, the membrane potential reaches a level

called the threshold potential, which is approximately -55 millivolts in a neuron If threshold is reached, an action potential results. An action potential is the basis for a nerve impulse When threshold potential is reached, sodium channels in the trigger zone open for an instant, briefly increasing sodium permeability Sodium ions diffuse inward and down the concentration gradient. The membrane potential changes from its resting value and momentarily becomes positive on the inside 4 DEPOLARIZATION AND ACTION POTENTIAL Nervous System The voltage-gated sodium channels close quickly, and slower voltage-gated potassium channels open and briefly increase potassium permeability

This continues as the nerve impulse moves along the axon Potassium ions diffuse outward, and the inside of the membrane becomes negative again. The membrane is repolarized The potassium channels close again and the resting potential is reestablished. It remains in the resting state until it is stimulated again For a short time following the passage of an impulse, a threshold stimulus will not trigger another impulse on an axon. This period is called the refractory period 4 NEUROTRANSMITTERS

Nervous System Neurotransmitters are released by exocytosis and travel across the synapse to the postsynaptic cell The action of a neurotransmitter is either: Excitatory turning a process on. Causes a muscle to contract or a gland to release secretions Inhibitory turning a process off. Causes muscles to cease contraction or a gland to stop releasing secretions The net effect of the neurotransmitters on a postsynaptic cell depends on the combined effect of the excitatory and inhibitory inputs from as few as one and as many as 100,000 presynaptic neurons 4 PARKINSONS DISEASE Progressive disorder

of the nervous system that affects movement Develops gradually, often starting with a barely noticeable tremor in one hand The exact cause of Parkinsons disease is unknown Nervous System Symptoms: Tremor Slowed motion Rigid muscles Impaired posture and balance Loss of automatic movements Speech changes Dementia 4

PARKINSONS DISEASE Prevalence: It is estimated that 6.3 million people have Parkinsons worldwide Nervous System Treatment: There is no cure for Parkinsons Disease, but medication can be used to treat its symptoms Surgery may be an option in some cases 4 Nervous System

MIGRAINE HEADACHES Severe headache that can cause intense throbbing or pulsing in one area of the head and is often accompanied by many other symptoms Migraine attacks can cause significant pain for hours to days Symptoms: Pain on one side of the head Pain that is pulsing or throbbing

Sensitivity to light, sounds, and sometimes smells Nausea and vomiting Blurred vision Diarrhea Lightheadedness, sometimes followed by fainting 5 MIGRAINE HEADACHES Prevalence:

About 8.7 million females and 2.6 million males in the US suffer from moderate to severe migraine headaches 3.4 million females and 1.1 million males suffer from one or more attacks per month Nervous System Treatment: Medications can help reduce the frequency and severity of migraines The right medicines combined with selfhelp remedies and lifestyle changes may help reduce the frequency and severity of migraine attacks

5 Nervous NERVOUS SYSTEM REFERENCE PAGE System Holes Human Anatomy & Physiology Textbook (Chapter 10 Nervous System I) prevalence-of-parkinsons-disease/ 5 REFERENCE PAGE (CONTINUED) Nervous System

Pictures: neurotransmitter.html 002_nervous_control/page_10.htm resting_potential.html 5 E TH E S S E S N M

E T S Y S 5 MECHANORECEPTORS Detect changes in pressure, position, or acceleration Specifically respond to mechanical energy, or movement Include receptors for touch, stretch, hearing, and equilibrium Most human mechanoreceptor cells respond to a change in external stimuli (pressure, temperature, etc.) by producing voltage pulses across neurons Found in:

Hair cells of the inner ear Stretch receptors within muscles Skin Bladder and parts of the alimentary canal (detect pressure) 5 THERMORECEPTORS Senses System Specialized to detect changes in temperature Generally detect temperature variations within normal range Help with the regulation of internal body temperature Found in: Skin, where they provide the brain with information about the environmental temperature Inside the body, where they help keep the bodys temperature in

balance 5 CHEMORECEPTORS Senses System Designed to respond to chemical stimuli - detect ions or molecules Chemoreceptors allow us to sense smell and taste There are direct and distant chemoreceptors all play important roles in bodily function and daily life Found in: Tongue sense salty, sweet, sour, and bitter tastes Carotid body located at the branch of the carotid artery Detect levels of oxygen and carbon dioxide in the blood to determine when a person needs to breathe Nose sense smells and detect hormones

Brain monitor pH and alert the brain to the presence of chemicals that could indicate a problem 5 PHOTORECEPTORS Senses System Nerve cells that are sensitive to light Three types Rods Cones Ganglion cells When a photoreceptor is exposed to light, photosensitive proteins are stimulated, triggering a series of responses which convert the light into a signal that can be read by the brain Photoreceptors provide constant information to the brain about

the visual environment Located in the eye 5 PAIN RECEPTORS Senses System Detect severe heat and pressure Detect chemicals released by inflamed tissue Activated in response to a painful stimulus, usually involving tissue damage

Once activated, they release neurotransmitters to send information to the brain Pain receptors found in tissues are called nociceptors Found on free nerve endings located in many tissues throughout the body, including: Skin Muscles Joints Connective tissues Internal organs 5 Senses System 6 RHODOPSIN AND CELL SIGNALING

Senses System Rhodopsin is a membrane protein in the retina of the eye Located in the disc membranes of the rod outer segments Pigment that allows us to see dim light Exposure to light causes rhodopsins shape to change. The structure of the protein is changed, activating rhodopsin Many different neurotransmitters, hormones, and drugs produce their intracellular signaling through the mediation of various G-protein coupled receptors. The binding of a hormone or neurotransmitter causes a change in the structure of the receptor which then activates

the G-protein So what? Rhodopsin is a G-protein binding receptor. It activates a G-protein, which may stimulate the opening of K+ channels (in heart cells) or participates as a part of the signaling system 6 SENSES SYSTEM REFERENCE PAGE Senses System bio%20102%20lectures/sensory%20systems/sensory.htm mechanorec.html Pictures:

6 E TH M L U C S U R A M E T S Y S 6 Muscular

System FUNCTIONS OF THE MUSCULAR SYSTEM Three types of muscle tissue Skeletal muscle Gives us the ability to have voluntary gross and fine movements (gross movements include large movements like the ones involved in walking, while fine movements include fine motor skills such as writing and talking) Skeletal muscles contract as a reflex to stimuli, such as pulling your hand away from a hot surface Smooth muscle Smooth muscles are found in the walls of the stomach and intestines. They aid digestion and help move food along the digestive tract Smooth muscle contractions are involuntary and characterized by slow movements Cardiac muscle Cardiac muscle forms the walls of the heart Contraction is involuntary and controlled by the hearts own electrical system Responsible for receiving blood and pumping it to the lungs and to the rest of the body 6 SKELETAL MUSCLE Muscular System

Skeletal muscle is striated, meaning the muscle fibers contain alternating light and dark bands (striations) Striations run perpendicular to the direction of the fibers Actin filaments make up the light bands (I-bands) Myosin filaments make up the dark bands (A-bands) Skeletal muscle tissue is highly organized, and each cell contains multiple nuclei Not all skeletal muscle fibers have the same structure, because they dont all have the same function They vary in color, which is dependent on the amount of myoglobin in the muscle tissue They contract with different velocities 6 SMOOTH MUSCLE

Muscular System Thin, elongated muscle cells Each muscle has a single nucleus Smooth muscle tissue is not as organized as skeletal muscle tissue. They are not arranged in a definite striated pattern Smooth muscle fibers interlace to form layers of muscle tissue rather than bundles 6 CARDIAC MUSCLE Muscular System Like skeletal muscle tissue:

cardiac muscle tissue is striated Each cell contains multiple nuclei Cardiac muscle cells are shorter than skeletal muscle fibers, and the striations are not as obvious as the ones seen in skeletal muscle Have intercalated disks to connect muscle fibers Because of this, cardiac muscle cannot cramp 6 Muscular System 6 Muscular System

6 THE SLIDING FILAMENT THEORY Muscular System The sliding filament theory explains how skeletal muscles contract Six main steps: 1. 2. 3. 4. 5. 6. Influx of calcium triggers the exposure of binding sites on actin Myosin binds to actin The power stroke of the cross bridges causes the sliding of the thin filaments ATP binds to the cross bridge, and the cross bridge disconnects from actin Hydrolysis of ATP leads to re-energyzing and repositioning of the cross bridge

Calcium ions are transported back into the sarcoplasmic reticulum 7 Muscular System THE SLIDING FILAMENT THEORY STEP 1 Acetylcholine, a neurotransmitter, crosses the neuromuscular junction and binds to an acetylcholine receptor site Acetylcholine causes calcium pumps to pump calcium ions out of the sarcoplasmic reticulum, where they have been heavily concentrated Calcium triggers the exposure of binding sites on actin 7 Muscular THE SLIDING FILAMENT THEORY STEPS System 2&3 Once calcium has exposed the binding sites of actin, myosin

and actin come into contact and bind together, forming myosin crossbridges At this point, myosin is in a high-energy state The binding of actin and myosin causes myosin (thick filaments) to pull actin (thin filaments), causing sliding of actin and myosin filaments Actin and myosin will remain bound together in this state unless they are pulled apart During this step, the shape of the myosin head changes, causing the ADP + Pi that has remained attached to the myosin head to fall out. This allows more ATP to bind to myosin 7 Muscular THE SLIDING FILAMENT THEORY STEPS System 4&5 At this time, myosin is in a low-energy state There is a low supply of ATP, and myosin needs more ATP in order to have another power stroke

The absence of ATP prevents myosin from remaining attached to actin. As a result, the myosin head falls off the actin When the ATP is attached to the myosin head, the ATP must be hydrolyzed in order to provide energy. Once the ATP is hydrolyzed, the products (ADP + Pi) remain in the ATP-binding site Causes myosin to be in a high-energy state once again 7 Muscular System THE SLIDING FILAMENT THEORY STEP 6 During the final step of muscle contraction, calcium ions are actively pumped back into the sarcoplasmic reticulum When another impulse arrives from the nervous system, calcium ions will once again leave the sarcoplasmic reticulum and start the cycle again Also, acetylcholine is broken down by the

enzyme acetylcholinesterase Muscle fibers relax 7 Muscular DUCHENNE MUSCULAR DYSTROPHY System A genetic disease in which muscle fibers are unusually susceptible to damage due to the absence of the muscle protein dystrophin Muscles burst upon contraction and die Muscle tissue is progressively replaced with scar tissue, causing death Occurs only in boys during late childhood or early puberty Signs and Symptoms: Frequent falls Difficulty getting up from a sitting position

Trouble running and jumping Waddling Large calf muscles Learning disabilities 7 Muscular DUCHENNE MUSCULAR DYSTROPHY System Prevalence: Approximately 1 in 6,000 people in the US have Duchenne Muscular Dystrophy Equal to 02% of the US population, or about 45,000 people There is no cure for Duchenne Muscular Dystrophy, but medications and therapy can

slow the course of the disease 7 Muscular System CHRONIC COMPARTMENT SYNDROME Chronic compartment syndrome is an exercise-induced condition that causes pain, swelling, and sometimes even disability in affected muscles (usually the lower leg) Anyone can develop chronic compartment syndrome Most common in athletes who participate in sports that involve repetitive movements such as running Caused by a high amount of pressure within a muscle compartment, which is surrounded by a thick layer of inelastic fascia As pressure builds up, nerves and blood vessels are compressed. Blood flow decreases, and nerve and muscle tissues may sustain damage or die 7 Muscular System CHRONIC COMPARTMENT SYNDROME Symptoms:

Aching, burning, or cramping pain in the affected limb Tightness Numbness or tingling in the affected limb Weakness Swelling or bulging as a result of a muscle hernia The prevalence of chronic compartment syndrome is unknown, because it is likely that affected people restrict activity due to pain caused by compartment syndrome and do not seek medical attention Treatment: Conservative treatments sometimes help with chronic compartment syndrome If conservative treatments fail, surgery is usually successful 7

Muscular System MUSCULAR SYSTEM REFERENCE PAGE sliding.htm DSECTION=symptoms 7

REFERENCE PAGE (CONTINUED) Muscular System Pictures: frogstriatedmusclesmall.html HB%20Lab%205/28.htm 8 E TH L E K S L A

T E M E T S SY 8 Skeletal System FUNCTIONS OF THE SKELETAL SYSTEM Support Provides structural support for entire body Protection Surrounds soft tissue (rib cage, skull) Movement

Skeletal muscles are attached to bones, allowing for movement Storage of minerals and fat Yellow marrow stores fat Storage of calcium and phosphorus Blood cell production Red bone marrow manufactures red and white blood cells 8 Skeletal ROLES OF BONES, LIGAMENTS, MUSCLES, AND TENDONS IN HUMAN System MOVEMENT Bones Bones fit together at joints, allowing for movement Bones and muscles together create a lever system. They can be classified as first, second, or third class levers Muscles Muscles provide the power to move the bones. They are responsible for flexing and extending joints, as well as other movements such as abduction and adduction

Ligaments Ligaments connect bones together. They are responsible for holding joints together Tendons Tendons attach muscles to bones. Without tendons, muscles wouldnt be able to pull and move bones 8 Skeletal System TYPES OF SKELETONS Hydrostatic skeleton Found in soft-bodied and cold-blooded animals Has a coelom surrounded by muscles Includes annelids and cnidarians Exoskeleton Skeleton found outside of the body, forms an outer protective covering Animals with an exoskeleton are relatively small Found in crustaceans, including crabs and insects Endoskeleton Skeleton found inside the body, forms the framework of an animal Tissues and muscles are formed around the skeletal system, muscular forces are transmitted to the skeleton Includes mammals, fish, and birds 8

PICTURE OF THE LONG BONE Skeletal System 8 Skeletal System RICKETS Rickets is the softening and weakening of bones in children, usually caused by an extreme and prolonged vitamin D deficiency Without vitamin D, calcium and phosphorus are not absorbed and are not deposited in bones, causing weakness and bending of the bones Signs and Symptoms: Delayed growth Pain in the spine,

pelvis, and legs Muscle weakness Bowed legs Abnormally curved spine 8 Skeletal System RICKETS Prevalence: In 1998 in eastern Turkey, the incidence of rickets was 6.09% in children ages 0-3 years Treatment: Adding vitamin D and calcium to the diet usually corrects bone problems

Some skeletal deformities caused by rickets may need corrective surgery 8 OSTEOPOROSIS Osteoporosis causes bones to become weak and brittle Bones are likely to fracture. Fractures commonly occur in the hip, wrist, or spine Occurs when the creation of new bone doesnt keep up with the renewal of old bone. Results in a loss of bone mass Affects men and women of all races, but white and Asian women who are past menopause are at the greatest risk

Skeletal System Signs and Symptoms: Back pain Loss of height over time Stooped posture A bone fracture that occurs more easily than expected 8 OSTEOPOROSIS Prevalence: Estimated to be a major health threat for almost 44 million U.S. women and men aged 50 and older By 2010, it is estimated that more than 52 million women and men aged

50 and over will be affected Skeletal System Treatment: Medications, dietary supplements, and weightbearing exercise can help to strengthen bones 8 Skeletal SKELETAL SYSTEM REFERENCE PAGESystem, +ligaments,+muscles,+tendons+%26+nerves+in+movement DSECTION=symptoms 9 REFERENCE PAGE (CONTINUED)

Skeletal System Pictures: 9

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