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Today

Today. Looking at “Form fits function” Human Body Review Have out notes, etc. that you need. Form fits function. Examples. Enzyme specificity Viral specificity Pollinators/flowers Pollen/stigma Adaptations/environment. Nervous System. Action potential.

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Today

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  1. Today • Looking at “Form fits function” • Human Body Review • Have out notes, etc. that you need

  2. Form fits function

  3. Examples • Enzyme specificity • Viral specificity • Pollinators/flowers • Pollen/stigma • Adaptations/environment

  4. Nervous System

  5. Action potential • http://outreach.mcb.harvard.edu/animations/actionpotential.swf • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html

  6. Transmission across synapses • http://outreach.mcb.harvard.edu/animations/synaptic.swf • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__transmission_across_a_synapse.html

  7. Muscular System

  8. Muscle Tissue • Skeletal– attached to bone (Ex. Biceps) • Smooth– blood vessels and internal organs (stomach) • Cardiac– heart • Reflex arc – pictured to the left

  9. Vertebrate Skeletal Muscle • Contract/relax: antagonistic pairs w/skeleton • Muscles: bundle of…. • Muscle fibers: single cell w/ many nuclei consisting of…. • Myofibrils: longitudinal bundles composed of…. • Myofilaments: •Thin~ 2 strands of actin protein and a regulatory protein •Thick~ myosin protein • Sarcomere: repeating unit of muscle tissue, composed of…. • Z lines~sarcomere border • I band~only actin protein • A band~actin & myosin protein overlap • H zone~central sarcomere; only myosin

  10. Muscle contraction • http://bcs.whfreeman.com/thelifewire/content/chp47/4702001.html

  11. Muscular contraction • Action potential travels from neuron to muscle • Action potential is generated on the sarcolemma • Sarcoplasmic reticulum releases Ca++ • Ca++ binds to troponin on the actin filaments • Conformational change exposes myosin binding sites

  12. Muscular Contration • ATP binds myosin head (high-energy head) • If Ca++ present, myosin binding sites on the actin are exposed (myosin heads bind to actin filaments) – form cross bridges • ADP and P are released, causes conformational change in myosin, causes sliding movement towards center of sarcomere (2 Z lines come together) • Muscle fibers contract

  13. Muscle contraction regulation, I • Relaxation: tropomyosin blocks myosin binding sites on actin • Contraction: calcium binds to troponin complex; tropomyosin changes shape, exposing myosin binding sites

  14. Muscle contraction regulation, II • Calcium (Ca+)~ concentration regulated by the…. • Sarcoplasmic reticulum~ a specialized endoplasmic reticulum – releases Ca+ • Stimulated by action potential in a motor neuron • T (transverse) tubules~ travel channels in plasma membrane for action potential • Ca+ then binds to troponin

  15. Endocrine System

  16. Mode of Action: Chemical Signaling • 1- Plasma membrane reception • signal-transduction pathways (neurotransmitters, growth factors, most hormones) • 2- Cell nucleus reception • steroid hormones, thyroid hormones, some local regulators

  17. TROPIC HORMONES Calcitonin T3/T4 Long-term Glucocorticoids Testosterone Estrogen Progesterone Short-term Epinephrine

  18. Respiratory

  19. Countercurrent exchange – allows diffusion to occur along the entire length of capillary • 80% efficient • On land, gills would dry out and collapse (need moist surface for diffusion)

  20. Regulating breathing • Regulation: monitors CO2 levels in blood (medulla oblongata) • CO2 + water = carbonic acid = lowers pH • Slight drop in pH triggers a breathing response • O2 levels have little effect on breathing unless O2 is severely depleted

  21. Respiratory pigments: gas transport • Needed for efficient transport of oxygen • Oxygen transport- • Hemocyanin: found in hemolymph of arthropods and mollusks (Cu) – blue blood • Hemoglobin: vertebrates (Fe) • Carbon dioxide transport- • Blood plasma (7%) • Hemoglobin (23%) • Bicarbonate ions (70%) • Deep-diving air-breathers- • Myoglobin: oxygen storing protein

  22. Protein review • Cooperativity – the binding of one oxygen to hemoglobin, causes the other 3 active sites to have a HIGHER AFFINITY for oxygen • Similar to allosteric activation • What do you think the optimal pH is for hemoglobin?

  23. Bohr shift • Hemoglobin releases oxygen (has less affinity for oxygen) at lower partial pressure for oxygen and at lower pH’s (more CO2)

  24. Circulation system evolution, I • Gastrovascular cavity (cnidarians, flatworms) • Open circulatory •hemolymph (blood & interstitial fluid) •sinuses (spaces surrounding organs) • Closed circulatory: blood confined to vessels • Cardiovascular system •heart (atria/ventricles) •blood vessels (arteries, arterioles, capillary beds, venules, veins) •blood (circulatory fluid)

  25. Circulation system evolution, II • Fish: 2-chambered heart; single circuit of blood flow • Amphibians: 3-chambered heart; 2 circuits of blood flow- pulmocutaneous (lungs and skin); systemic (some mixing) • Mammals: 4-chambered heart; double circulation; complete separation between oxygen-rich and oxygen poor blood

  26. The heartbeat • Sinoatrial (SA) node (“pacemaker”): sets rate and timing of cardiac contraction by generating electrical signals • Atrioventricular (AV) node: relay point (0.1 second delay to ensure atria empty) spreading impulse to walls of ventricles • Electrocardiogram (ECG or EKG)

  27. Why do the blood vessels have different structure? • Capillaries•endothelium (lining of smooth cells = less resistance to blood flow); basement membrane – cell attachment & selective permeability • Arteries•thick connective tissue; thick smooth muscle; endothelium; basement membrane • Veins•thin connective tissue; thin smooth muscle; endothelium; basement membrane

  28. Blood • Plasma: liquid matrix of blood in which cells are suspended (90% water) • Erythrocytes (RBCs): transport O2 via hemoglobin • Leukocytes (WBCs): defense and immunity • Platelets: clotting • Stem cells: pluripotent cells in the red marrow of bones • Blood clotting: fibrinogen (inactive)/ fibrin (active); hemophilia; thrombus (clot)

  29. Digestion

  30. Feeding mechanisms Substrate-feeders Suspension-feeders Deposit-feeders Bulk-feeders Fluid-feeders

  31. Intracellular Digestion • Ingestion – phagocytosis, pinocytosis • Digestion – hydrolytic enzymes contained in lysosomes • Absorption – simple diffusion • Elimination - exocytosis

  32. Extracellular Digestion – can eat larger prey Gastrovascular cavity Complete digestive tracts (alimentary canals) – allow for systematic Food processing in specialized regions 2 openings 1 opening

  33. Gastric Pits

  34. Positive feedback mechanism

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