Chapter 40

1. Chapter 40 Physiology, Homeostasis, & Temperature Regulation

2. Terms • Anatomy-structure • Physiology-function • Homeostasis-maintenance of a stable internal environment • Feedback loop

3. Parts of a feedback loop • Receptor • Receives stimulus • Control Center (set point) • CNS: brain or spinal cord • Effector • Produces a response • Usually a muscle or a gland

4. Feedback loops • Negative • result is changed/opposed • most are this type • Ex: body temperature; blood pressure • Positive • result is repeated/enhanced/reinforced • only a few are this type • Ex: blood clotting; childbirth

5. 6 Organizational Levels • Chemicals (atoms, molecules, macromolecules) • Cellular • Tissue • Organ • Organ System • Organism

7. 4 tissue types • Epithelial • Connective • Muscle • Nervous

8. Epithelial • Avascular • Has nerve supply • Easily renewable • Functions: protection, secretion, absorption, excretion, sensory reception • Classified by cell shape and layer arrangement

9. Epithelial cell shape • Squamous-flat and thin • Cuboidal-cube-shaped • Columnar-tall and cylindrical • Transitional-cell shape changes

10. Epithelial layer arrangement • Simple-single layer • Stratified- two or more layers • Pseudostratified-one layer that appears to have several layers

11. Simple Squamous Epithelium • Structure: • Single layer of flat thin cells • Function: • diffusion • Location: • Alveoli of lungs; capillaries; heart lining

12. Simple Cuboidal Epithelium • Structure: • Single layer of cube-shaped cells • Function: • Secretion and absorption • Location: • Ducts of glands; ovarian surface

13. Simple Columnar Epithelium • Structure: • Nonciliated: single layer of tall & narrow cells without cilia • Ciliated: single layer of tall & narrow cells with cilia • Function: • Nonciliated: secretion (Goblet cells) and absorption • Ciliated: movement of mucus • Location: • Lines tracts with environmental openings

14. Pseudostratified Epithelium • Structure: • 1 layer of tall & narrow cells that appears to be more than 1--but it is not • Ciliated (w/ cilia) and nonciliated (no cilia) • Function: • Secretion & movement of mucus • Location: • Lines airways of upper respiratory tract

15. Pseudostratified - ???

16. Stratified Squamous Epithelium • Structure: • 2 or more flat, thin layers • Function: • protection • Location: • Esophagus, tongue, vaginal lining, epidermis of the skin

17. Stratified Cuboidal Epithelium • Structure: • 2 or more layers of cube-shaped cells • Function: • Protection; limited secretion and absorption • Location: • Sweat gland ducts

18. Stratified Columnar Epithelium • Structure: • 2 or more layers of tall & narrow cells • Function: • Protection & excretion • Location: • Conjunctiva of eye; excretory ducts

19. Transitional Epithelium • Structure: • Appearance of cells ranges from squamous to cuboidal & columnar • Function: • Allows for stretching without tearing (distensibility) • Location: • Urinary bladder

20. Glandular Epithelium a/k/a Glands • Glands: consists of a cell or group of cells that secrete substances into ducts, onto surfaces, or into blood • 2 types: • Exocrine: secretion goes through a duct • Ex. Sweat, oil, saliva, pancreas • Endocrine: secretion goes into blood stream without passing through a duct • Ex. Thyroid, pituitary, & pancreas

21. Connective Tissue • Most abundant and widely distributed tissue in the body • Consists of cells and a matrix (determines a tissues qualities; may be fluid, gel, fibers) • Has a nerve supply • Highly vascular (except cartilage)

22. Mature Connective Tissue • Areolar • Adipose • Dense Regular • Dense Irregular • Elastic • Cartilage • Compact Bone • Blood

23. Areolar Connective Tissue • Location • Subcutaneous layer of skin • Function • Strength • Support • elasticity

24. Adipose Connective Tissue • Location • Around heart, kidneys, eyes, and in yellow bone marrow • Function • Energy reserve and protection

25. Dense Regular Connective Tissue • Location • Tendons • Muscle to bone • Ligaments • Bone to bone • Function • attachment

26. Dense Irregular Connective Tissue • Location • Fascia: covers organs • Periosteum: covers bones • Perichondrium: covers cartilage • Pericardium: covers heart • Function • Provides strength

27. Elastic Connective Tissue • Location • Lung tissue, trachea, vocal cords, bronchial tubes • Function • stretching

28. Cartilage • Location • Nose, voice box, epiglottis, external ear, pubis symphysis • Function • Support, cushioning, rigidity, flexibility

29. Compact Bone • Location • Bones (osteocytes) • Function • Support, protection, storage

30. Blood • Location • Blood vessels, heart • Function • Transport gases, immunity, clotting

31. Nervous Tissue • Tissue of the nervous system • Basic functioning unit = neuron

32. The neuron • Cell body (soma) • Dendrites (many) • Axon (one)

33. Muscle Tissue • 3 types • Skeletal • Smooth • Cardiac

34. Skeletal Muscle • Attaches to bones of skeleton • Striated (striped) in appearance • voluntary

35. Smooth Muscle • Makes up walls of internal organs • Nonstriated • Involuntary

36. Cardiac Muscle • Found in heart • Striated with intercalated discs • involuntary

38. Membranes • Tissues that cover or line a part of the body • 3 types • Mucous • Synovial • Serous

39. Mucous Membranes • Line body cavities that open to the environment • Secrete mucus • Ex: digestive system, reproductive system, respiratory system

40. Synovial Membranes • Line the cavities of some joints • Secrete synovial fluid • Lubricates joints to prevent friction during movement • Bursae are often present here as well • bursitis

41. Serous Membranes • Line body cavities that do not open to the environment • Secrete serous fluid • 2 layers: • Parietal: lines cavity wall • Visceral: covers organ(s) • 3 locations: • Lungs = pleura • pleurisy • Heart = pericardium • pericarditis • Abdomen = peritoneum • peritonitis

42. How Does Temperature Affect Living Systems? Body temperature of some animals is coupled to environmental temperature. In winter, a fish will acclimatize to colder water by expressing different isozymes. Isozymes that are optimized at different temperatures can catalyze the same metabolic reaction.

43. HowDo Animals Alter Their Heat Exchange with the Environment? Thermal classification of animals can be based on source of heat. Ectotherms have external sources of heat. Endotherms regulate temperature by producing heat metabolically or by actively losing heat. Heterotherms can behave either as an ectotherm or an endotherm.

44. Major differences between ectotherms and endotherms: • Resting metabolic rate • Total energy expenditure when at rest • Response to changes in environmental temperatures

45. Figure 40.9 Ectotherms and Endotherms React Differently to Environmental Temperatures (A)

46. Figure 40.9 Ectotherms and Endotherms React Differently to Environmental Temperatures (B)

47. An endotherm will increase its metabolic rate to maintain its body temperature in cold conditions. Both endotherms and ectotherms may use behavioral regulation to maintain body temperature. Example: moving into sun

48. Figure 40.10 Ectotherms and Endotherms Use Behavior to Regulate Body Temperature (Part 1)

49. Figure 40.10 Ectotherms and Endotherms Use Behavior to Regulate Body Temperature (Part 2)

50. 40.3 How Do Animals Alter Their Heat Exchange with the Environment? Both ectotherms and endotherms can alter heat exchange between their bodies and the environment. Body temperature is determined by the balance between internal heat production and four types of heat exchange.