1. UNIT XII – ANIMAL PHYSIOLOGY II Digestive, Reproductive, Nervous, Muscular Systems Big Campbell – Ch. 41, 46, 47, 48, 49, 50 Baby Campbell – Ch 21, 27, 28, 30 Hillis – Ch 32, 33, 34, 36, 39

2. ANIMAL NUTRITION & DIGESTION

3. I. NUTRITION Undernourishment  Caloric deficiency Overnourishment  Excessive food intake  Obesity Malnourishment  Essential nutrient deficiency Macronutrients  Essential nutrients  Materials that must be obtained in preassembled form  Essential amino acids  8 amino acids that must be obtained in the diet  Essential fatty acids  Unsaturated fatty acids

4. I. NUTRITION, cont Micronutrients:  Vitamins - Organic coenzymes  Water Soluble:  B Vitamins – Required for general metabolism  Vitamin C – Required for connective tissue production  Fat Soluble:  Vitamin A – Vision  Vitamin D – Ca 2+  Vitamin E - ???  Vitamin K – blood clotting  Minerals - Inorganic cofactors  Na  Ca  Fe  K  P  I  Cl

5. I. NUTRITION, cont Feeding Types & Adaptations Opportunistic  Herbivore  Carnivore  Omnivore Feeding Adaptations  Suspension-feeders  Sift food from water  Baleen whale  Substrate-feeders  Live in or on their food  Earthworm  Fluid-feeders  Suck fluids from a host  Mosquito  Bulk-feeders  Eat large pieces of food  Most animals

6. II. DIGESTION Overview Of Food Processing Ingestion Digestion  Enzymatic hydrolysis  Intracellular: breakdown within cells (sponges)  Extracellular: breakdown outside cells (most animals)  Gastrovascular cavity vs. alimentary canal Absorption Elimination

7. III. HUMAN DIGESTION Peristalsis - rhythmic waves of contraction by smooth muscle Sphincters - ring-like valves that regulate passage of material Accessory glands - salivary glands; pancreas; liver; gall bladder

8. III. HUMAN DIGESTION, cont Oral cavity  Salivary amylase  Bolus – wad of food formed from mechanical, chemical digestion Pharynx  Epiglottis Esophagus  Food tube  Contents moved through cardiac sphincter

9. III. HUMAN DIGESTION, cont Stomach  Gastric juices – Made up of  Mucus  Pepsin/pepsinogen  HCl  Partially-digested stomach contents known as chyme  Pass through pyloric sphincter to small intestine

10. III. HUMAN DIGESTION, cont Small Intestine  Site of most digestion, nutrient absorption  Divided into 3 regions Duodenum  First 12 inches  Na Bicarbonate  Bile  Hydrolytic enzymes

11. III. HUMAN DIGESTION, cont Jejunun & Ileum  Villi/microvilli  Contain vessels from circulatory system, lymphatic system  Nutrient absorption carried out through diffusion, active transport  Capillary networks  Amino acids, monosaccharides aborbed into circulatory system  Transported to liver via hepatic portal vein  Lacteal  Vessels from lymphatic system  Transport chylomicrons – water-soluble droplets of fats mixed with cholesterol Hepatic portal vessel – carries contents from nutrient-rich capillaries to liver

12. III. HUMAN DIGESTION, cont

13. Large Intestine or Colon  Cecum / Appendix  Water reabsorbed from secreted digestive juices  Contents moved along by peristalsis  Diarrhea  Constipation  Huge population of normal bacterial flora  Feces – undigested food (cellulose), dead bacteria Rectum  Waste storage  2 sphincters  Waste expelled through anus

14. III. HUMAN DIGESTION, cont

15. Hormones Involved in Digestion – Leptin  Produced by adipose cells  Increased amount of adipose tissue = increased levels of leptin = decreased appetite – Gastrin  Produced by stomach  Food triggers release of gastrin → returns to stomach wall → stimulates secretion of gastric juice – Enterogastrone  Produced by duodenum  Inhibits peristalsis and acid secretion by stomach, slows digestion when chyme with high fat concentration enters duodenum – Secretin  Produced by duodenum  Stimulates pancreas to release Na bicarbonate to neutralize chyme – Cholecystokinin (CCK)  Produced by duodenum  Stimulated by presence of amino acids/fatty acids in duodenum → Triggers release of pancreatic digestive enzymes, bile from gallbladder

16. IV. DIGESTIVE EVOLUTIONARY ADAPTATIONS Dentition - Animal’s assortment of teeth Digestive system length Symbiosis Ruminants

17. IV. EVOLUTIONARY ADAPTATIONS, cont Ruminant Digestion

18. HUMAN REPRODUCTION

19. I. GAMETE PRODUCTION

20. II. REPRODUCTION – MALE HUMAN ANATOMY Testes  Contained in scrotum  Importance of temperature  Seminiferous tubules – sperm formation  Leydig Cells – produce testosterone & other hormones  Sertoli Cells Epididymis  coiled tubules that sperm pass through from testis Vas deferens  Muscular tube that propels sperm during ejaculation Ejaculatory Duct  Combines sperm from both testes; leads to urethra Glands  Seminal vesicles – Add fluid to protect nourish sperm, including fructose, mucus, enzymes; produces semen  Prostate gland - Secretes anticoagulant, nutrients into semen  Bulbourethral glands – Secretes acid neutralizer before ejaculation Penis/Urethra  Ejaculation - Release of semen  Blockage of urine flow controlled by sphincters

21. II. REPRODUCTION – MALE, cont Human Sperm

22. III. REPRODUCTION – FEMALE HUMAN ANATOMY Ovaries  Follicle – Egg capsule; nourishes and protects egg  Egg released during ovulation  Corpus luteum – Secretes estrogen and progesterone to maintain uterine lining; formed from follicle after egg is released Oviduct  Also known as fallopian tube  Egg moved along through action of cilia Uterus  Thick, muscular organ also known as womb  Endometrium – inner lining  Cervix – opens into vagina

23. IV. REPRODUCTIVE CYCLES Estrous Cycle  Seen in animals  Uterine lining is reabsorbed by the uterus if pregnancy does not occur; no bleeding  Causes more pronounced behavioral changes  Animals typically only copulate during ovulation; known as estrus Menstrual Cycle  Seen in humans, other primates  Oogenesis occurs during the ovarian cycle  Ovarian cycle is synchronized with menstrual cycle through the action of hormones  Divided into phases  Follicular phase – growth of follicle  Ovulation – release of egg  Luteal phase – degeneration of corpus luteum

24. V. MENSTRUAL REPRODUCTIVE CYCLE Follicular Phase Small amounts of FSH and LH are secreted by the pituitary The follicle is stimulated to grow, leading to secretion of estrogen (estradiol) Initially, low levels of estrogen inhibit secretion of FSH, LH (negative feedback)

25. V. MENSTRUAL REPRODUCTIVE CYCLE, cont Ovulation As estrogen concentration continues to increase increase in growing follicle, at a critical concentration, estrogen concentration switches to positive feedback mechanism. FSH and LH production increase, especially LH Causes release of follicle

26. V. MENSTRUAL REPRODUCTIVE CYCLE, cont Luteal Phase LH stimulates remaining follicular tissue to transform into corpus luteum Due to effects of LH, corpus luteum secretes progesterone, estrogen Increasing concentrations of progesterone, estrogen exert negative feedback on pituitary, decreasing release of FSH, LH As levels continue to decrease, corpus luteum disintegrates Results in sharp decrease in estrogen, progesterone levels At a certain point, levels drop beneath concentration required for negative feedback to pituitary → pituitary then begins secreting FSH, LH → cycle begins again

27. VI. FERTILIZATION Fertilization:  Sperm reaches egg  Head of sperm contains a vesicle known as the acrosome ; contains enzymes that help sperm penetrate egg  Acrosomal reaction – hydrolytic enzymes act on egg jelly coat  Surface proteins on sperm bind with receptor molecules on egg  Sperm cell membrane fuses with egg cell membrane  Cell membrane of egg depolarizes, becomes impenetrable to sperm to prevent multiple fertilization (polyspermy)  Triggers increase in metabolic activity in fertilized egg (including completion of meiosis II)

28. EMBRYONIC DEVELOPMENT

29. I. EMBRYONIC DEVELOPMENT

30. Cleavage Cleavage produces a ball of cells known as a blastula  Cells known as blastomeres  Cavity formed known as blastocoel Nutrients stored in the egg known as yolk Two sides of the blastula  Vegetal pole – Side with high yolk concentration; larger cells due to yolk; divide more slowly  Animal pole – Side with low yolk concentration; smaller cells; divide at a faster rate

31. I. EMBRYONIC DEVELOPMENT - Amniotes Forms within a shell or uterus Extraembryonic membranes  Yolk sac – Contains blood vessels that transport nutrients from yolk to embryo  Amnion – Fluid-filled sac; protection  Chorion – Formation of placenta  Allantois – Disposal sac for nitrogenous wastes; incorporated into umbilical cord in mammals

32. II. GASTRULATION Formation of blastopore Cells migrate to form three embryonic tissue layers  Ectoderm – outer layer; develops into epidermis, nervous system  Mesoderm – middle layer; develops into skeletal, muscular, excretory systems, heart  Endoderm – inner layer; forms digestive tract & associated organs, respiratory organs, etc Simple digestive cavity formed from endoderm known as archenteron Gastrula formed

33. III. ORGANOGENESIS Organogenesis

34. IV. FETAL DEVELOPMENT Gestation – pregnancy First Trimester  Organogenesis  By week 8, human fetus has all adult features  Corpus luteum maintained by HCG ; prevents menstruation; also used to detect pregnancy Second Trimester  Refinement of human features  Corpus luteum degenerates; placenta begins secreting progesterone Third Trimester  Rapid growth  Respiratory, circulatory systems prepare for breathing Parturition - birth  Estrogen levels increase; trigger formation of oxytocin receptors  Fetus, mother’s pituitary gland secrete oxytocin which triggers uterine contractions, preparation for lactation  Following birth, mother’s pituitary gland secretes prolactin ; stimulates milk production, continued uterine contractions

35. NERVOUS SYSTEM Phineus Gage 1823 - 1860

36. I. NERVOUS SYSTEM Human Nervous System

37. II. CELLS OF THE NERVOUS SYSTEM Glia o Support cells o Mostly nonconducting cells that provide support, insulation, protection  Astrocyctes  Schwann cells - PNS  Oligodendrocytes - CNS Neuron o Basic unit of function o Three types  Sensory Neurons  Convey signals from sensory receptors to CNS  Interneurons  Integrate, interpret data; relay signals to other neurons  Motor Neurons  Convey signals from CNS to effector cells (glands or muscles)

38. II. CELLS OF THE NERVOUS SYSTEM, cont A Closer Look at a Neuron  Dendrite  Cell Body  Axon o Myelin Sheath o Nodes of Ranvier  Axon (Synaptic) Terminal  Synapse

39. II. CELLS OF THE NERVOUS SYSTEM, cont

40. III. NEURAL SIGNALING Membrane potential (voltage differences across the plasma membrane) Selective permeability of plasma membrane creates intracellular/extracellular ion concentration gradient o High concentration of Na + outside Net negative charge of about -70mV

41. III. NEURAL SIGNALING, cont Neurons, muscle cells → excitable cells; cells that can change membrane potentials Gated Ion Channels → open/close response to stimuli → photoreceptors; vibrations in air (sound receptors); chemical (neurotransmitters) & voltage (membrane potential changes) Hyperpolarization → opening of K + channels; results in outflow of K + ; increase in electrical gradient Depolarization → opening of Na + channels; results in inflow of Na +

42. III. NEURAL SIGNALING, cont Threshold – Stimulus strong enough to increase voltage to ~ -50mV; triggers an action potential Caused by movement of ions through Na +, K + voltage-gated channels Sequence of events:  Resting State – Channels closed  Depolarization – Na + channels open; inside of cell becomes +  Repolariztion - Na + channels close; K + channels open slowly → K + ions leave → cell returns to negative  Hyperpolarization – Created by K + gates; close very slowly → K + ions continue flowing out of cell → brief period where cell is more negative than resting state. Known as refractory period – neuron is insensitive to depolarization until resting potential is restored

43. III. NEURAL SIGNALING, cont Movement of the action potential is self-propagating Regeneration of “new” action potentials only after refractory period Forward direction only Speed of action potential related to  Axon diameter  Nodes of Ranvier; known as saltatory conduction

44. III. NEURAL SIGNALING, cont Transmission of Impulse Across a Synapse Synaptic Cleft – small gap between sending neuron and receiving cell Synaptic vesicles contain neurotransmitter molecules Action potential causes synaptic terminal to depolarize → Ca 2+ channels open → Ca 2+ flows in → causes vesicles to fuse with axon terminal membrane Neurotransmitters “spit out”; diffuse across synapse  Excitatory Postsynaptic Potentials (EPSPs)  Inhibitory Postsynaptic Potentials (IPSPs) Examples of neurotransmitters include acetylcholine, dopamine, epinephrine, norepinephrine, serotonin

45. III. NEURAL SIGNALING, cont

46. III. NEURAL SIGNALING, cont A Review

47. IV. VERTEBRATE PNS

48. IV. VERTEBRATE PNS, cont Nerves  Bundles of sensory & motor neurons  12 pairs of cranial nerves  31 pairs of spinal nerves

49. IV. VERTEBRATE PNS, cont Reflex - “Automatic” response; sensory to motor neurons

50. V. VERTEBRATE CNS Brain Spinal Cord Protected by 

51. V. VERTEBRATE CNS, cont Human Brain Forebrain  Cerebrum  Cerebral Cortex  Corpus Callosum  Thalamus  Hypothalamus Midbrain – Receives & transmits sensory info to forebrain Hindbrain  Cerebellum  Pons  Medulla oblongata

52. V. VERTEBRATE CNS, cont

53. ANIMAL MOVEMENT

54. I. INTRODUCTION TO MOVEMENT Gravity, friction must be overcome Types of Movement  Swimming  Flying  Locomotion on land Importance of Skeleton  Support  Protection  Essential to Movement  Hydrostatic Skeleton  Found in  Exoskeleton  Found in  Endoskeleton  Found in

55. II. SKELETAL MUSCLE FUNCTION Typically at least 2 attachment sites  Origin  Insertion Muscles of appendicular skeleton make up antagonistic pairs  Flexor  Extensor Muscles  Bundle of muscle fibers  Multinucleated cells  Composed of myofibrils

56. II. SKELETAL MUSCLE FUNCTION, cont Muscle myofibrils made up of two types of myofilaments  Thin Filaments  Two strands of actin  Wrapped with protein complex made up of tropomyosin and troponin complex  Thick filament  Myosin Contracting unit of muscle tissue known as sarcomeres Sliding Filament Theory  When stimulated, actin & myosin filaments slide past each other; overlap increases  Shortens sarcomere length

57. II. SKELETAL MUSCLE FUNCTION, cont Sliding-Filament Model, I Myosin binds ATP; hydrolyzed to ADP + P i Myosin head changes shape; termed high energy configuration Myosin head binds to specific site on actin; forms a cross bridge ADP and P i released; myosin relaxes to low energy configuration Causes actin to slide toward center of sarcomere Binding of new ATP releases myosin head

58. II. SKELETAL MUSCLE FUNCTION, cont Muscle Contraction Regulation, I Relaxation  Tropomyosin blocks myosin binding sites on actin Contraction  Calcium binds to troponin complex  Tropomyosin changes shape  Exposes myosin binding sites

59. II. SKELETAL MUSCLE FUNCTION, cont Muscle Contraction Regulation, II Stimulated by action potential in a ________________ neuron _____________________ triggers depolarization of muscle fiber by opening _____________ voltage-gated channels Action potential spreads to infoldings of cell membrane called T (transverse) tubules Sarcoplasmic reticulum = specialized ER that actively transports calcium ions When action potential reaches places where T tubules touch sarcoplasmic reticulum → Ca 2+ released Ca 2+ then binds to troponin, allowing myosin binding sites to be revealed

60. III. OVERVIEW OF SKELETAL MUSCLE FUNCTION

61. IV. SKELETAL MUSCLE ADAPTATIONS Energy Availability Adaptations   Creatine Phosphate  Myoglobin  Fast-twitch Fibers Slow-twitch Fibers