Introduction to Anatomy and Physiology

1. Introduction to Anatomy and Physiology

2. anatomy = “a cutting open” • Study of internal and external structures of the body and the physical relationship between body parts • Ex – a particular bone attached to a muscle

3. physiology • Study of the function of anatomical structures; considers both physical and chemical processes • Ex. how a muscle contracts to move the bone

4. cell: basic unit of life • Cytology • Histology

5. Levels of Organization

9. Homeostasis Objectives: Significance of homeostasis Positive and negative feedback

11. Start here

12. Lots of examples of negative feedback loops, few positive loops For test be able to analyze: • Calcium homeostasis (page 132) • Body temperature (page 7) • Water regulation (refer to notes) • Control center for sympathetic and parasympathetic divisions of PNS • Effectors and response after sympathetic disruption of homeostasis occurs

13. Two ways to maintain homeostasis • Negative feedback • Positive feedback

14. Negative Feedback: example body temperature

15. Q1: compare response to original stimulus • Answer: • The response by the effectors is antagonistic (opposite) of the stimulus Stimulus = body temp ↑ Response = body temp ↓

16. Q2: homeostasis restored? How do you know? • Answer • Yes, because the response counteracts the stimulus • Brings back balance

17. Positive Feedback: example labor contractions

18. Q3: compare response and stimulus in positive feedback • Answer • The response acts to heighten or increase the stimulus Stimulus = ↑ distortion of uterus Response= ↑ distortion and contraction of uterus

19. Q4: Is homeostasis restored in this example? How do you know? • Answer: • No, homeostasis is continually disrupted • This is a good thing in this case b/c returning to homeostasis would cause the birthing process to stop. • The positive feedback loop will continue until birth is complete.

20. Positive feedback examples • Childbirth • Blood clotting • Sexual orgasm • Milk production from mammary glands

21. Cellular homeostasis Every level of organization within the body must maintain homeostasis Phospholipid Bilayer

22. Diffusion • Diffusion is the movement of molecules from a higher concentration to a lower concentration. • The difference in concentration of two solutions is called the concentration gradient • Demonstration: food coloring in water ttp://www.biosci.ohiou.edu/introbioslab/Bios170/diffusion/Diffusion.html

23. Diffusion: Anatomy example • Oxygen gas enter body and blood stream • Carbon dioxide leave blood and body

24. Molecules that dissolve in lipids can cross the lipid bilayer through diffusion. Example: O2 CO2 H2O Diffusion across membranes

25. Osmosis • Think back to solutions: solutes and solvents • Osmosis is the process by which water molecules diffuse across a cell membrane from an area of lower solute concentration to an area of higher solute concentration. • Direction of movement depends on relative concentrations of solutions.

26. Osmosis: anatomy connection • Excess water versus dehydration • Kidneys help to rid excess water as urine = osmosis of water out of blood (high) into kidneys (low)

27. Direction of movement into cells • Hypotonic to the cytosol • solution outside the cell is less concentrated than inside the cell • water moves into the cell • Hypertonic to the cytosol • solution outside the cell is more concentrated than inside the cell • water moves out of the cell • Isotonic • concentrations are equal • http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm

28. What about the molecules that can’t pass through the membrane freely? • Glucose, Na+, Ca+, K+ and lots of other molecules need to get into and out of the cell but can’t get through the lipid bilayer • They must use the proteins embedded in the lipid bilayer

29. Facilitated transport • Protein channels embedded in the cell membrane allow ions and other molecules to diffuse into and out of a cell • Where have we seen facilitate diffusion in action? • Neuron’s gated Na+ and K+ channels • Ca+ channels in nerve and muscle cells

30. Active transport • Requires energy to transport molecules across a cell’s membrane Ex. 1 Membrane proteins may serve as pumps to push ions across the cell against the concentration gradient • Examples of pumps? • Na+/K+ pump in neurons

31. Active Transport (con’t) Ex. 2 Exocyotosis – the cell excretes wastes, chemicals or other products by releasing them from vesicles • Where have we seen this? • Release of neurotransmitters Ex 3 Endocytosis – the cell takes in molecules or food by engulfing it • We will see this with immune system and WBCs