Anatomy & Physiology Intro (Part 2)

Transcription

1 Anatomy & Physiology Intro (Part 2) BME Introduction to Biomedical Engineering James A. Smith Original Reference:

2 Physiology

3 Overview What is physiology? From cell to human (levels of organization) A review of the organ systems Introduction of the concept of homeostasis Themes in Physiology The science of Physiology Experimental design Data

4 Physiology is the study of the function of all plants and animals in their normal state. an integrative science

5 Levels of Organization

6 Organ Systems operate as integrated units How many? Can you list them? Examples: Regulation of Plasma calcium concentration Blood pressure etc.

7 Function and Process: Approach to Science What is purpose or function? Why does something exist? Why does it need to be done? What are processes involved? How does something work?

8 Distinguish between Process & Function How do we breathe? How does blood flow? How do RBCs transport O 2? Why do we breathe? Why does blood flow? Why do RBC transport O 2? Integrate both for complete picture!

9 Focus on.... (Concept) Mapping 1. Structure function maps 2. Process maps or Flow charts Follow process in sequence

10 Key Themes in Physiology: Homeostasis Body systems work together (Integration of function) Internal vs. external failure of homeostasis Communication and movement across cell membranes Vital to integration & homeostasis Cells communicate with other cells, tissues & organs

11 Molecular Interactions Inorganic Chemistry C, O, H, Na, S, P, Mg, K, Ca, Fe + trace elements Ions (variable electrons) Neural pathways Isotopes (variable neutrons) Nuclear Medicine Organic Chemistry Carbon, Hydrogen & Oxygen in Biomolecules Proteins Fats Nucleotides (RNA, DNA)

12 Cells & Tissues Cells are dynamic Stem cells: general to specialized Apoptosis: programmed cell death Tissues are dynamic How do organs change over time?

13 Metabolism All chemical reactions that take place within an organism Energy - for synthesis & movement Enzymes = Biological Catalysts Lower energy requirements in conversion ATP Cycle

14 Membrane Dynamics Cell membrane structures and functions Membranes form fluid body compartments Membranes as barriers and gatekeepers Products move across membranes Distribution of water and solutes in cells & the body

15 Homeostasis Control Systems Sense & Regulate subsystems

16 Temperature Regulation Video

17 Matlab Control Demo Switch to Matlab & VR Toolbox (vpend)

18 Endocrine System The study of hormones, their receptors, the intracellular signaling pathways they invoke, and the diseases and conditions associated with them. Hormones Secreted by cells into blood Rapid effects Limited duration Combinations can be useful!

19 Neurons: Electrifying! Electrical signaling Changes in membrane electrical potential are the basis for electrical signaling Only nerve and muscle cells are excitable (= able to propagate electrical signals)

20 Sensory Systems Receptors are transducers convert stimuli into electrical potential Chemo- Chemo- (specific ligands) and Osmo- (conc.. of solutes) Mechano- (touch, pressure, vibration, stretch) Thermo- Thermo- (temp. change) Cold receptors lower than body temp. Warm receptors (37-45 o C) > 45 Photo- (light) C) > 45 o C?

21 Muscles: Molecular Interaction ATP ADP + P i Tight binding between G-actin and myosin No nucleotide bound ATP binds dissociation

22 Released energy changes angle between head & long axis of myosin Myosin head acts as ATPase Rotation and weak binding to new G-actin Relaxed muscle state when sufficient ATP

23 Power stroke begins as P i released ADP released Tight binding to actin Myosin crossbridge movement pushes actin

24 Heart Depolarization

25 Blood Flow Blood pressure must be regulated Flow from high to low pressure Resistance: radius, viscosity and length Too Low Pumping (force) cannot overcome gravity Oxygen diminished to brain Too High Weakened arterial walls -> rupture! Cerebral hemorrhage

26 Blood Control Hemostasis = Opposite of hemorrhage stops bleeding Too little hemostasis too much bleeding Too much hemostasis thrombi / emboli Vessel damage exposes collagen fibers Platelets adhere to collagen & release factors local vasoconstriction & platelet aggregation + feedback loop decreased blood flow platelet plug formation

27 Oxygen exchange Air to blood Blood to cells (?) Carbon dioxide exchange Cells to blood Blood to air Regulation of body ph Functions of the Respiratory System CO 2 + H 2 O H 2 CO 3 H + + HCO - 3 Protection from pathogens, irritants Vocalization

28 The Kidneys Urinary Processes 1. Filtration, 2. Reabsorption, 3. Secretion, 4. Excretion 5. Micturition 180 L / day filtered, >99% reabsorbed, 1.5 L/day excreted

29 Fluid Balance Many subsystems! Kidneys: key role Balance water via urine concentration React to osmolarity, volume, blood pressure

30 The Digestive System Major processes of digestive system: 1. Motility 2. Secretion 3. Digestion 4. Absorption

31 The Immune System Three Major Functions 1. Protection from disease-causing invaders 2. Removal of dead /damaged tissues & cells 3. Recognition & removal of abnormal cells 3. Immunologic mistakes: 1. Incorrect responses: autoimmunity 2. Overactive responses: allergy 3. Lack of response: immune deficiency

32