Exam 1 Flashcards
Physiology
Study of how living organisms work
Functions, processes, and integrations within living things
Knut Schmidt Nielson
Alternative physiology definition
Study of how organisms work requiring heuristic metric of when organisms are and are not working well
George Bartholomew
Every level of biological organization finds its mechanism at lower levels and its significance at higher levels of the organization
What are the 3 General categories of chemical messengers?
- Hormones- released into blood stream for delivery
- Neurotransmitters- released directly to target cell
- Paracrine- triggers response in cells around it
Autocrine- releases and comes back to trigger something on the same cell
What are the major body compartments and their percentages of they hold?
Plasma- 7%
Interstitial Fluid- 28%
Intracellular Fluid- 67%
Aristotle
Shaped the way we go about doing science with morality, aesthetics, logic and systematic
Galen
Deduced a pattern of blood flow through the body, first to document this, was wrong
William Harvey
First to correctly document the circulation of blood pumped through the body
Claude Bernard
Father of modern Physiology
Milieu Interieur
Constancy of the internal environment is the condition for a free and independent life
Walter Cannon
Coined the term Homeostasis
Mechanisms that detect and respond to deviations in physiological variables form their set point values by initiating effector responses that restore the variables to the optimal physiological range
What are the components of homeostatic systems?
Sensors (receptors)- monitor detect variables
Integration center- place that processes the information (brain)
Effector- responds to bring back to set point
What mechanism primarily maintains homeostasis in the body?
Negative feedback, detects and corrects
Afferent pathway
carry signals towards integrating center
Stimulus -> receptor -> integrating center
Efferent Pathways
integrating center -> Effector -> Response
Carry signals away from integrating center towards effector
Dynamic Constancy
Levels shifting throughout the day, high to low to normal
Body Temp regulation:
Mechanism?
Steps (components):
Negative feedback
Stimulus- deviation cold or hot
Receptors- signaling rate increases in temperature sensitive nerve endings
Integrating center- nerve cells in brain alters their rates of firing
Result- Heat loss- constriction of the smooth muscles in skin blood vessels (white hands)
Heat production- skeletal muscle contraction leading to shivering
Where are the hormones of the pancreas secreted from?
What are two of the cell types?
Pancreatic Islets
Beta cells-insulin
Alpha cells- Glucagon
Insulin
Decreases blood glucose levels
Stimulates transport of glucose into liver, skeletal muscles and adipose (fat) tissue where it is stored
Glucagon
Increases glucose in the blood by converting glycogen to glucose in the liver
Diabetes mellitus
metabolic disorders characterized by an abnormally high level of glucose in the blood
Excess urine (sweet urine), increased thirst, increased appetite
Excess urine production
polyuria
increased thirst
polydipsia
increased appetite
polyphagia
Diabetes mellitus
Mechanism?
What happens?
Steps:
Negative Feedback
Blood is supposed to absorb the glucose and water but this does not occur causing the individual to lose water and sugar in urination
Low glucose: Pancreas secretes glucagon -> Liver breaks down glycogen to glucose -> blood glucose increases
High glucose: pancreas secretes insulin -> muscle cells take up glucose OR adipose tissue uses glucose to form fat OR liver stops breakdown of glycogen to glucose
Positive feedback
and pathway
response reinforces the stimulus sending the parameter farther form the setpoint
Continues until outside factor is present to turn it off
Factor -> sensor -> integrating center -> effector
Labor and delivery
Mechanism?
Steps:
Positive Feedback
1. Baby’s head triggers stretch receptors in the cervix
2. Firing of receptors change sending message to the brain
3. Hypothalamus releases oxytocin into bloodstream
4. Oxytocin triggers contractions
5. Contractions casue baby’s head to push harder on the cervix
6. Steps 1-5 are repeated
7. Baby is born -> no more stretch -> process stops
Fluid-Mosaic Model
Used to describe our cell membranes.
Not ridged, dynamic in constant motion made up of different parts and pieces
Describe the Structure of a phospholipid
Polar, hydrophilic head and a nonpolar, hydrophobic tail
Amphipathic
Has both polar and nonpolar components
In our cells it creates the bilayer, affecting the passage of material in and out of the membrane
Saturated vs unsaturated fats
Saturated are tightly packed, viscous with single bonds
Unsaturated can’t be packed as tightly allowing more motion (fluid) and has one or more double bonds
Membrane Fluidity
Measure of the ease with which phospholipids can move within the membrane
Indicated by the amount of saturated vs. Unsaturated fats
Homeoviscous Adaptation
Maintenance of a relatively constant membrane fluidity
Changing the phospholipids
Higher temp= increase fluidity
Lower temp+ more ridged
Peripheral vs Integral proteins
Peripheral- On one side of the layer or the other, bonded to integral proteins or lipids
Integral- embedded in the bilayer
What is the role of Cholesterol in the bilayer?
Regulates membrane fluidity
The more cholesterol the more ridged the structure
How are solutes transported across the cell membrane?
Simple diffusion, facilitated diffusion, active transport, endo and exocytosis
Simple Diffusion, and example
Passive process (no ATP), moves down concentration gradient (high to low), freely passing through lipid bilayer until equilibrium is reached (equal movement)
Must be small and lipid soluble
Ex: blood gases (oxygen), and steroids
Rate Factors
Define
List
Factors that influence diffusion
Lipid solubility (faster), Molecular size (smaller=faster)
Cell membrane thickness (thicker=slower), Concentration gradient (higher difference= faster), Membrane surface area, Composition of lipid layer