Physiology Test #1

The study of normal functioning of a living organism and it's component parts (Systems, organs, tissues etc.)

1. The body's ability to maintain a relatively constant internal environment while desired substances pass in and out of cell

2. Involves all organs, tissues and cells

3. BP, pH, Temperature, Glucose levels, Hormones

-Operate to maintain homeostasis
1. Measure existing value of some factor (ie. body temp--normally 37C)
2. Compare it to a selected point value (i.e. 38C)
3. Employ the difference between the 2 values and start physiological changes ,', return to point value

Components to Neg. FB. Loop
1. Stimulus (drives)2. Receptors (detect)3. Integration Centre (decides)4. Effectors (doers)5. Response (did it change?)

Intracellular fluid-- (inside the cell) Cytoplasm
Interstitial fluid--(extracellular) Fluid between cells --transition btw external environment and intracellular fluid

Plasma--(extracellular) liquid component to our blood

When excessive fluid consumption dilutes salt levels and creates a sodium imbalance in the body. In an effort to reverse this imbalance, cells allow water to seep in, causing them to swell. Most cells can manage, but because the brain has little room in the skull, even slight swelling can result in big problems, including disorientation, loss of consciousness, seizure and death.

Local Control Systems
-Specialized cells sense a change and take action to fix it--only surround concerned area. (i.e. noticing low O₂ levels in the blood)

Long Distance Control Systems
-More complex and involved multiple components. Homeostatic feedback loop is designed to keep body at or near a set point (feedback loop is - or + BUT the Negative Feedback loop is homeostatic)

1. Composition of Lipid Bilayer2. Surface Area3. Lipid Solubility4. Molecule Size5. Membrane Thickness6. Concentration Gradient

Autocrine Signals- a signal acts on inself (the cell that made it)

Paracrine Signals- the signal acts on adjacent cells

Contact Dependent Signals-Surface molecules on one cell membrane bind to a membrane protein of another cell

Gap Junctions- Protein Channels called connexins net like bridges ,', there's a direct transfer of chemical and electrical signals (fund in heart ,', fast communication btw cells)

Chemical signals made by any type of cell in response to a stimulus
(i.e. Autocrine Signal, Paracrine Signal, Contact Dependent Signal, Gap Junctions...)

Tonicity-The ability of a solution to cause osmosis across biological membranes

note: Osmolarity of body fluids is 300 mosmoles/kg

Isotonic =300 mosmoles/kg o --> o

Hypertonic >300 mosmoles/kg O --> o

Hypotonic <300 mosmoles/kg o --> O

Osmosis
-The net movement of water down its concentration gradient

Osmotic Pressure
-Pressure applied to exactly oppose the osmotic movement of water (measured in mmHg)

Osmole
-# of particles used in a calculation to be able to predict/measure osmosis


Osmolarity
-the # of particles (ions/intact molecules) per L of solution (Units: osmol/L)

Note: Osmolarity of glucose-- It doesn't break apart therefore when calculating osmolarity, it is considered one ion/particle.

Chemical Gradient
molecules tend to move from areas of high concentration to low concentration (i.e. they move down the chemical gradient)

Electrical Gradient
Many solutes within our bodies carry a charge (i.e. Ca²⁺ or Cl^-). Electrically charge molecules (ions) move toward areas of opposite charge (,', when ions move down its electrical gradient, positively charged ions are moving to negatively charged ions)

Resting Membrane Potential
typically negative ions (anions)accumulate inside the cell membrane and positive ions (cations) accumulate outside of cell membrane ** since this potential difference is present across the plasma membrane even in resting cells, it's called RMP.

1. Organism (Human Body)2. Organ Systems (Digestive System)3. Organ (Stomach)4. Tissues (Layers of Tissue in stomach wall)5. Cells (a cell in stomach lining)

-Body systems exposed to external environments are the most likely to get sick:

External:
1. Respiratory System2. Digestive System3. Urinary System4. Reproductive System

Internal
1. Musculoskeletal System
2. Endocrine System3. Nervous System
4. Circulatory System

C-Cytoskeleton
-internal frameowrk that enchors organellea
C-Centrioles
Aids in cell division and formation of spindle fibres for mitosis
L-Lysosome
-breaks down proteins and digests food
G-Golgi Apparatus
-packaging and secretion of proteins and exports inside and outside of cell
S(ER)- Smooth Endoplasmic Reticulum
-fat metabolism
M-Mitochondria-Produce ATP by converting glucose (C₆H₁₂O₆) into CO₂, H₂O and ATP
R(ER)- Rough ER
-Associated with Ribosomes and makes secretory and membrane Proteins
​N- Nucleus
Contains genetic material and controls cell's activities like cellular division