Flashcards in L1: Homeostasis & Cell Fxn Deck (31):
What is human physiology?
Study of the functional organization of the human body
What is homeostasis?
Refers the to the maintenance of nearly constant conditions in the internal environment
What conditions define an organism in homeostasis?
Has optimum concentrations of gases, nutrients, ion, and water
Optimal pressure for health of the cells
What is stress?
Any stimulus that creates an imbalance in the internal environment
List basic difference between extracellular and intracellular.
Extracellular has larger amounts of sodium, chloride, and bicarbonate
Intracellular has larger amounts of Potassium, magnesium, PO4/organic prtn., & protein
Which cation is most abundant in the extracellular fluid?
Which cation is most abundant in the intracellular fluid?
Which anion is most abundant in the extracellular fluid?
Define feedback system.
A circular situation in which the information about the status of something is continually reported to a central control region
What is a negative feedback loop?
A change in some parameter causes a response that results in a return of that parameter to normal.
The response reverses the direction of the initial condition.
What is a positive feedback loop?
A change in some parameter causes a responses that continues to change that parameter in the same director as before.
The input is intensified.
Compare negative & positive feedback.
Negative feedback diminishes the original change and stabilizing.
Positive feedback enhances the original change and destabilizing can lead to runaway effects.
Give example of negative feedback loop.
Regulation of arterial blood pressure
Baroreceptors sense increase in arterial pressure
Baroreceptors send inhibitory signals to vasomotor receptors in medulla
Heart pumping capacity reduces and blood vessels dilate
Arterial pressure decreases
Give example of positive feedback loop.
Pregnancy - delivery
-Stretch of the cervix sends back signals
-That increase the force of uterine contractions
-Which then increase the stretch on the cervix
There is a natural end to this feedback, which is child birth.
Most instances there's no natural end to the feedback
the degree of effectiveness with which a control system maintains constant conditions
How do you calculate gain in a feedback system?
Gain = Correction / Error
Give example of a gain calculation
Adding to liters of blood to an uncontrolled system & a controlled system
UCTRL: pressure rises 100-175
CTRL: pressure rises 100-125
Homeostatic control system has counteracted (corrected) the potential increase by -50
Error is the amount of uncorrected increase = 25
Gain = correction/error = -50/25 = -2
Describe the universal structure of cellular membranes w/respect to phospholipids & proteins.
Phospholipid bilayer w/ cholesterol inserted
hydrophilic heads / hydrophobic tails
integral proteins inserted in membrane
peripheral protein loosely attached
What is the characteristics of substances necessary to pass across cell membranes?
lipid soluble (non polar) can pass readily across membrane
What is the difference between peripheral and integral proteins?
Peripheral = loosely attached
integral = inserted into membrane
What are some of the basic functions of the plasma membrane?
Separate extra cellular and intracellular
regulate what enters and leaves cell
plays role in info exchange
involved in exocytosis / endocytosis
List & describe function of the major organelles found in the eukaryote cell.
peroxisomes and endosomes
With which function is clathrin associated?
what is the purpose of endocytosis?
to form phagocytic vesicles
What are some characteristics of lysosomes?
Involved in digestion
Contain hydrolytic enzymes at a low pH
Result of a hydrogen pump
Primary lysosomes fuse with phagocytic vesicles to form secondary lysosomes
Undigested material is left behind within residual bodies
Residual bodies may be eliminated via exocytosis
What organelles are associated with protein synthesis?
Compare Glycolysis & the Kreb's cycle with regard to oxygen requirement and end products.
-starts with glucose & occurs in cytoplasm
-anaerobic - occurs without oxygen
-produces pyruvic acid (lactic acid) and small amounts of ATP
-starts with pyruvic acid and occurs in mitochondria
-aerobic - occurs with oxygen
-produces CO2, H2O, and much more ATP
Outline the pathway for intracellular trafficking and secretion.
Glycosylation is sugar attaching to proteins.
Proteins are formed in the RER
Lipids are formed in the SER
Transported to Golgi apparatus
Once packaged ready to be delivered
Then secretory vesicles will transport it
Describe types of locomotion used by individual cells.
Amoeboid movement - used by macrophages and some leukocytes
Cilia - move other material, but the cell stays stationary
Flagella - moves cell, but only cell in human is sperm cells
Microtubules - provide tracks on which motor molecules can move cargos
Which organelle/s is/are associated with intracellular trafficking?