Homeostasis and Cell Function Syed Flashcards
What is human physiology?
Study of the functional organization of the human body
What are homeostatic mechanisms made up of?
Adaptive responses - a change occurs, we act, then return to original state
An organism is said to be in homeostasis when its internal environment:
- Contains the optimum concentrations of gases, nutrients, ions, and water
- Has an optimal temperature
- Has an optimal pressure
Which cations/anions are in the extracellular vs. intracellular?
Extracellular: Na+, Cl-
Intracellular: K+, MG2+, Phosphate
Example of negative feedback loop?
In increase in the production of TSH releasing factor results in an increase in the release of thyroid stimulating hormone, which results in the release of more thyroxine, which results a decrease in the production of TSH releasing factor.
What is a negative feedback loop?
A change of a parameter that causes a response, that results in a return of that parameter back to it’s normal. The response reverses the direction of the initial condition.
Give another example of a negative feedback loop
Regulation of arterial blood pressure - Baroreceptors in the arterial walls can sense increase in arterial pressure. They send inhibitory signals to the vasomotor receptors in the medulla (controls heart rate). The pumping is reduced and blood vessels dilate. Pressure decreases.
What is a positive feedback loop?
A change of a parameter that causes a response to continue to change that parameter in the same direction. The input is intensified.
Give an example of positive feedback loop
Childbirth: Stretch of cervix sends back signals that increase the force of uterine contractions, when then increase the stretch on the cervix.
What is Gain?
It’s the degree of effectiveness with which a control system maintains constant conditions. Equation: Correction/Error
Calculate gain: Uncontrolled - 100 to 175
Controlled - 100 to 125
The correction is -50. The error (uncorrected increase) is 25. -50/25 = -2
Which of the following would have to be a transmembrane protein: A receptor protein A protein binging to the cytoskeleton A channel protein A phosphorylase
A channel protein
What can be considered organelles?
Something that has a membrane - so no microtubules
How are peripheral proteins attached to the membrane?
By proteins called Glycophosphatidylinositol = GPA-anchored proteins
How does cholesterol affect the cell membrane?
Cholesterol is relatively inflexible, so it reduces membrane fluidity. More cholesterol = less fluidity
Difference between integral and peripheral membrane proteins
Integral proteins are inserted into the lipid bilayer and can go through the whole thing
Peripheral proteins are linked indirectly to the membrane by protein-protein interactions.
What organelles are associated with intracellular trafficking?
Golgi, ER(smooth and rough), and technically microtubules and vesicles too
Which organelle is directly associated with the synthesis of proteins for secretion?
Rough ER
Difference between pinocytosis and phagocytosis
Both are a form of endocytosis. Pinocytosis is cell fluid drinking. Phagocytosis is cell eating.
Explain Lysosomal digestion
The primary lysosomes fuse with phagocytic vesicles to form secondary lysosomes.
Undigested material is felt behind within residual bodies
(Figure 2-12)
Explain the difference between the two protein synthesis ribosome locations
- Proteins bound for lysosomes or for secretion are synthesized on Rough ER to which ribosomes attach
- Proteins bound for the cytoplasm, nucleus, mitochondria, or to other cell membranes are synthesized on free ribosomes
What are the duties of the Golgi Apparatus
- Plays a role in protein packaging for secretion
- Forms lysosomes
- Modifies proteins from the Rough ER
What are some methods of locomotion?
Amoeboid movement - Used by macrophages and some other leukocytes
Flagella (sperm cells) and Cilia - Cilia move material though a layer of mucous that coats a layer of ciliated cells. Cells remain stationary
Microtubules - provide tracks
