human systems physiology

Circulatory system

Transport of materials between all cells of the body (heart, blood vessels, blood)

Musculoskeletal system

Support and movement (skeletal muscles, bone)

Nervous system

Coordination of body function through electrical signals and release regulatory molecules (Brain, spinal cord)

Respiratory system

Exchange of oxygen and carbon dioxide between the internal and external environments (lungs, airways)

Urinary system

Maintenance of water and solutes in the internal environment (bladder, kidneys)

Physiology: chemical level

A molecule in the membrane that encloses a cell

Physiology: cellular level

A cell in the stomach lining

Physiology: tissue level

Layers of tissue in the stomach wall

Physiology: organ level

The stomach

Physiology: body system

The digestive system

Physiology

Functions of structures (respiration, circulation, digestion)

Homeostasis

The maintenance of constant, stable conditions in the body

Conditions that are maintained by homeostasis

Water concentration, plasma volume & pressure, temperature, concentration of nutrients, electrolyte concentration, pH

A simple control system

Input signal > integrating center > output signal > response

Negative feedback

Self-regulating control system where a change in a internal condition triggers a response that counters that initial change

Positive feedback

A control mechanism where a change in a variable triggers a response that amplifies the initial change moving the system away from its normal state

Elephantasis

Excess fluid in the extra cell fluid

Epithelial tissue

Protection, secretion, absorption

Connective tissue

Structural support, interstitial “space”

Muscle tissue

Movement

Nervous tissue

Communication, coordination, control

Total body water (L)

Body weight (kg) x water %

Intracellular fluid

2/3 TBW

Extra cellular fluid

1/3 TBW

ECF compartments

Interstitial fluid (3/4) and plasma (1/4)

How to nutrients transfer from stomach to blood

Across epithelial

Requires ATP

Passive

Uses pre-existing energy

Active

Cell barriers with selective permeability

Gated channel, leak channel, carrier protein

Bulk flow

Mass movement of gases

Gradients

Pressure (lungs, heart, blood), concentration (glucose, oxygen), electrical (ions and charged particles)

Osmolarity

The measure of solute concentration in a solution

Osmotic pressure ______ water and balances out because hydrostatic _____

Pulls, pushes

Isotonic

K+ and Na+ are even in and out

Hypotonic

Less water out, water moves into cells

Hypertonic

More water out, less water inside the cell

Leak channels

Always open , no stimulus

Aquaporins

Similar to leak channels but specific to water, not needed for water flow but increases it

Gated-channel

Opened by stimulus, ligand gated (key/lock), voltage gated, sensory receptors (temp, pH, light, etc.)

ECF K and Na levels

Higher Na and lower K, Na binds to pump w ATP

ICF K and Na levels

Lower Na and higher K, K binds to pump w ADP