Human Physiology

1. Human Physiology Chapter 12: the study of how living things work

2. Barron’s Essential 5: #3 Molecules, cells, and organs coordinate activities for the fitness of the organism as a whole.

3. Digestion A.) Digestion Is the breakdown, whether mechanical orchemical, of our food, macromolecules, into smaller useable and absorbable form B.) Absorption C.) Egestion Diffusion of broken down molecules into body cells Removal of undigested waste

4. Digestive System 1. Mouth 2. Esophagus 3. Stomach 4. Duodenum 5. Latter Small Intestines 6. Large Intestines 7. Rectum 8. Anus http://resources.teachnet.ie/farmnet/Digestive.htm

5. Mouth • Mechanical breakdown of food withchewing • Chemical breakdown with initiation of starch breakdown by salivary amylase secreted by salivary glands Note: Specialization of teeth; Incisors for cutting, Canines for tearing, Premolars and Molars for grinding 2. Esophagus Movement of chewed food (Bolus) to stomach by involuntary muscle contractions known as Peristalsis http://resources.teachnet.ie/farmnet/Digestive.htm

6. Stomach • Mechanical digestion in churning • Chemical digestion of proteins Note: Different types of cells in the Stomach that coordinate for protein digestion: i.) Chief cells secrete inactive Pepsinogen ii.) Parietal cells secrete hydrochloric acid in which providing a pH of 2-3 in the stomach environment to activate pepsinogen into pepsin http://resources.teachnet.ie/farmnet/Digestive.htm ...iii.) And a third type of cell that secretes mucus for stomach lining...

7. 4. Duodenum Complete digestion of molecules in first 12 inches of small intestines Note: Pancreatic amylases hydrolyze starch and glycogen in maltose Bile, from liver, stored in gall bladder emulsifies fat into fat droplets for further digestion Lipases breaks down fat completely Peptidases, such as trypsin or chymotrypsin breaks down proteins Nuclease hydrolyzes nucleic acids http://resources.teachnet.ie/farmnet/Digestive.htm

8. 5. Small Intestines Absorption of molecules by villi and microvilli fingerlike projections to optimize surface area Note: Amino acids, vitamins, and monossacharides are absorbed into capillary network of villus Fatty acids and glycerol go into lacteal which leads into the lymphatic system as a small vessel 6. Large Intestines Responsible for egestion, vitamin production and removal of excess water (approx. 90%) http://resources.teachnet.ie/farmnet/Digestive.htm Note: Undigested waste is stored in rectum and eliminated through anus as feces

9. Hormones Regulating Digestive System

10. Respiratory System Main function is for Gas Exchange (of O2 and CO2 for cell use) • Air Pathway: • Nasal Cavity-moistens, warms, andfilters air • Larynx • Trachea • Bronchi • Bronchiole • Alveoli- diffusion of respiratory • gases Note: Rib cage expands, diaphragm contracts and lowers, and chest cavity (thoracic cavity) expands which draws air in by negative pressure http://antranik.org/the-respiratory-system/

11. Detouring... To fully understand the respiratory system itself and its role within the body, we must take recall the Circulatory System http://blog.vixra.org/2012/02/07/stop-rumours/

12. Circulatory System A closed circulatory system in humans has the function of transporting nutrients,gas exchange, and taking away toxic waste through the medium of blood circulation. Note: The system consists of the heart, arteries, veins, and capillaries Arteries-carry blood away from heart; thick walls of elastic smooth muscle Veins-carry blood back to heart by valves and skeletal muscle contractions that propels blood to move Capillaries-allow for diffusion of nutrients and wastes between cells and blood

13. Content of Blood Carries hemoglobin and oxygen; no nucleus, 120 day life span; formed in bone marrow and recycled in liver Fight infection; formed in the bone marrow; die fighting infection, pus; B lymphocytes produce antibodies Liquid portion; contains clotting factors, hormones and antibodies, dissolved gases, nutrients, and wastes. Maintains proper osmotic potential. Cell fragments; formed in bone marrow; clots blood

14. [Side] Blood Clotting • Clotting factors from platelets • Anticlotting factors in plasma to prevent thrombus formation Damaged Tissue->Thomboplastin + Ca2+->Prothrombin (inactive) -> Thrombin (active) ->Fibrinogen (inactive)-> Fibrin (Clot) (Active)

15. Heart Composed of 4 chambers: two atria, two ventricles; right or left ventricle or atrium Note: Cardiac muscle cells can contract even when removed from heart --Own innate pacemaker, sinoatrial node S A A V SA node then to atrioventricular (AV) node to contract http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.3532069/ Note2: Electrical impulses travel through cardiac and body tissues, where can be detected by electrocardiogram (EKG)

16. Pathway of Blood Right atrium Right atrioventricular valve(tricuspid) Right ventricle Pulmonary semilunar valve Pulmonary artery Lungs (Pulmonary circuit) Pulmonary vein Left atrium Bicuspid (left AV) valve Left ventricle Aortic semilunar valve Aorta Systemic circuit http://www.tutorvista.com/content/biology/biology-ii/transportation/circulation.php Note: Systemic circuit consists of coronary circulaiton, renal circulation, and hepatic circulation.

17. Going back... The medulla in the brain contains the breathing control center—sets rhythm of breathing and monitors CO2 levels in blood by sensing changes in pH. CO2 is the by-product of cellular respiration, dissolves in blood to form: Carbonic Acid Therefore, higher [CO2], lower pH Blood pH <7.4 causes medulla to increase rate of breathing --There are O2 sensors (chemoreceptors) to a lesser degree

18. Continuing Internal RespirationHemoglobin Oxygen loosely carries 4 oxygen molecules Unique in having allosteric properties but also exhibits cooperativity Once binds to an O2 molecule, it changes conformation to allow other oxygen molecules to better bind A drop in pH alters affinity for oxygen. This is known as the Bohr shift. CO2 emitted by actively respiring cells induces an acidic environment as CO2 dissolves to form carbonic acid. As the hemoglobin approaches to a a more acidic environment, it will release its oxygen into the cell where needed.

19. Transport of Carbon Dioxide Reversible blood buffering carbonic acid-bicarbonate ion system

20. Excretory System • Functional unit of the kidney is the nephron • Consists of a cluster of capillaries, the glomerulus, sits inside Bowman’s capsule, and connects to the renal tubule • Nephron carries out filtration, secretion, reabsorption, and excretion • Filtration is passive and nonselective. • Specialized cells in Bowman’s capsule modified into podocytes and along with slit pores, increase the rate of filtration • Everything small enough to diffuse out of the glomerulus includes glucose, salts, vitamins, waste such as urea, and other small molecules • Filtrate travels into the proximal tube • Secretion is active and highly selective • Occurs in proximal and distal tubules • Uptake of certain drugs and toxic molecules, secretes ammonia to neutralize the acid • Reabsorption is passive, active, and selective. • Water and solutes are transported back into the body • Process occurs in the proximal convoluted tubule and loop of Henle and collecting tubule • Loop of Henle acts as countercurrent exchange mechanism to maintain steep salt gradient surrounding the loop • Excretion is removal of metabolic wastes, urines passes through the ureter to the urinary bladder and passes out the body via the urethra. • Aldosterone is hormone released by the adrenal glands in response to a decrease in blood pressure. • ADH, vasopressin, produced by the hypothalamus is stored and released from the posterior pituitary in response to dehydration.

21. Nervous System • Central nervous system consists of the brain and spinal cord. • Peripheral nervous system consists of all nerves outside the CN • Neuron consists of a cell body which contains the nucleus, dendrites and axons • Dendrites are sensory and receive oncoming messages • Axons transmit an impulse outward to another cell • Axons wrapped in a fatty myelin sheath formed by Schawnn cells

22. Sensory neurons receive initial stimulus • Motor neuron stimulates effectors • Internueron transfers information directly to the motor neuron or to the brain for processing • Reflex arc is inborn, automatic, and protective • Sensory neuron transmits an impulse to the interneuron in the spinal cord

23. Neurotransmitters http://txtwriter.com/Backgrounders/Drugaddiction/drugs1.html

24. Allliving cells exhibit a membrane potential • Cytoplasm(negatively charged) and extracellular fluid(positively fluid) • Stimulus must be enough to overcome the resting potential • Sodium ion-gated channel, results in depolarized and easier for the nerve to fire • Potassium ion-gated channel results in hyperpolarization, harder for neuron to fire • Action potential generated in the axon of the neuron • Sodium channels and potassium channels open • Wave of depolarization reverses the polarity of the membrane • Sodium-potassium pump restores the membrane to its original polarized condition, refractory period, neuron cannot respond to stimulus

25. The body distinguishes strong and weak stimulus by the frequency of action potentials • Impulse crosses a synapse chemically • Cytoplasm at the terminal branch of the presynaptic neuron contain many vesicles that contain molecules of neurotransmitter • Depolarization cause Ca++ ions to rush through calcium-gated channels • Neurotransmitter released by exocytosis, and bind with receptors on the postsynaptic side • Neurotransmitter release into the synapse is destroyed by esterase • Neurotransmitter at neuromuscular junction is acetylcholine, others are serotonin, epinephrine, norepinephrine, and dopamine

26. Cerebrum • Learning, emotion, memory, perception • Cerebellum • Coordinates movement and balance • Receives sensory information • Brainstem • Controls several automatic homeostatic functions, breathing, heart and blood vessel activity • Integrates sensory information • Sensory phase of vision • Photons of light pass through the lens which focuses light on retina • Light is absorbed by photoreceptors when it strikes the retina in neurons – rods( black and white) and cones( color vision) • Stimulation of retinal activates a G protein-signaling mechanism that alters the membrane potential and closes Na+ channels • Each molecule of photoexcited rhodopsin activates enzyme molecules which activate cGMP closing Na+ channels and causing impulse to be sent to the optic nerve and cortex of the brain where messages are interpreted • Another opsin molecule has evolved by means of gene duplication and has generally enhanced our colour vision. However when the gene is nonfunctional it results in red-green colour blindness in men

27. Chemical Signals Two major regulatory chemicals: Hormones and Neurotransmitters --as seen, neurotransmitters regulated by nervous system while hormones controlled by excretory system

28. Hormones produced in ductless (endocrine glands) moves through blood to a target cell short-lived response *Refer to Barron’s page 235 Overview of Hormones

29. Hypothalamus Bridge between the endocrine and nervous systems– ultimately two functions. Stress- Nervous function, sends out electrical signals to adrenal gland to release adrenaline http://www.studyblue.com/notes/note/n/limbic-system/deck/1241563 Nervous, when releasing gonadotrpoic-releasing hormone(GnRH) to stimulate anterior pituitary to secret FSH and LH. Endocrine, when releasing oxytocin and antidiuretic hormones

30. Ways Hormone Stimulate • Lipid or Steroid Hormone • Diffuse directly through the plasma membrane and bind to receptor • in nucleus to trigger cell response • Protein or peptide hormone (nonsteroidal) • cannot dissolve in the plasma membrane, so they bind to a receptor on • of cell, triggering secondary messenger c-AMP inside cell to convert • extracellular chemical signal to a specific response.