Lecture 1 Flashcards
(29 cards)
Human physiology
Study of the functional organization of the human body
Homeostasis
Refers to the maintaenance of nearly constant conditision in the internal environment
It is the condition in which the body’s internal environment remains relatively constant wihtin limits
A homestatic mechanism is made up of adaptive responses . Responsible for holding up physiology
When is an organims in homeostasis?
- Contains the optimum concentration of gases ,nutrients, ions and water
- Has an optimal temperature
- Has an optimal pressure for health of the cells
Stress
Any stimulus that creates an imbalcne i nthe internal environment
Which cation and anion is most abundant in extracelluluar fluid
Sodium and chloride
Which cation is most abudnant in intracellular fluid
Potassium
Feedback system
Circular situation in which the information about the status of something is continually reported to a central control region
Negative feedback loops
A change in some parameter(ex. blood pressure) causes a response that results in a return of that parameter to normal(baseline). The response reverses the direction of hte initial condition
Charecteristics:
Diminishes the original change
stabilizing
Ex. Regulation of arterial blood pressure
How does the arterial blood pressure loop work
- Baroreceptors(type of stretch receptor located in aterial walls) associated with the carotid system sense increase in arterial pressure
- Baroreceptors send inhibitory signals to vasomotor receptors in medulla
- Heart pumping capacity is reduced and blood vessels dilate
- Arterial pressure decreases
Positive feedback loops
A change in some paramter causes a response that continues to change that parameter in the same direction as before. The input is intensified
Charecteristics: Enhances the original change Destabilizing CAn lead to runaway effects Most positive feedback loops are catastrophic
Cervix positive feedback loop
- Stretch of the cervix during delivery sends back signals that icnrase the force of uterine contractions which then increase the stretch on the cervix
- Note that in this example, there is a natural end to the intitial stretch in the form of childbirth, which then terminates the feedback loop
- In most instances,there is no natural end to the feedback , and the process exceeds limits conductive to life
This loop works becasue there is a natural end
Gain
The degree of the effectiveness with which a control system maintains constant conditions
Nothing is perfect including control systems
by uncontrolled system means that htier is no homesotatic mechanisms
equation= correction/error
want your number to be big and negative because that tells you the effectivness of the feedback mechanism
Which of the following would have to be a transmembrane protein?
- A receptor protein
- A protein binding to they cytoskeleton
- A channel protein
- A phosphorylase
Channel protein
Strucutre of the cell membrane
All cell membranes(plasma as well as htose around organelles have the same strucutre
Have phospholipid bilayer with cholesterol inserted among the phospholipids
Proteins are associated with the membrane
1.Integral proteins are eitehr insreted into the membrane on one side or the other or pass all the way through and are exposed on either sdie of the membrane
2.Peripheral proteins are loosely attached to one surface of the membrane or the other and are easily removed
Vital for controlling intracellular fluids, if penetrated, cells dies
Peripheral proteins only need hydrophilic domains
How are peripheral proteins attached to the membrane?
Attached by a glycophosphatidylinositol=GPI-anchored proteins
Cholestereol
A major membrane component but it does not form the mebrane by itself
Has an effect on membrane fluidity by modulation the movement of the fatty acid chains of phospholipids in a temperature dependent manner
What does the otuer leaflet of the celleluar membrane consist of ?
Consists mainly of phosphatidylcholine,sphingomyelin,and phosphatidylethanoiamine.
Glycolipids are found only in the outer leaflet with their carbohydrate portion exposed to the extracellular space
What does the inner leaflet of the cellular membrane consist of ?
- Inner leaflet consists mainly of phsophatiylserin, phosphatidylinositol ,and phosphatidylethanolamine.
- The head groups of phosphatidylserine and phosphatidylinsoitol are negtaivly charged , so the cytosolic face of the plasma membrane has a net negative charge. Phosphatidylinositol plays a siginifcant role in signaling
The function of the plasma membrane
- Serves as a selective filter and limits what can pass from one side to the other
- Lipid soluble substances can generally pass readily across the membrane
- Plays an importnat role in defining hte intracellular and extracellular fluid composition
- Plays a role in information exhcange between the cell and its environment
- Intimately invovled in exocytosis and endocytosis(Pinocytosis and phagocytosis)
Which Organelle(s) is/are associated with intracellular trafficking?
Er, golgi
Which organelle(s) is/are assoicated with most ATP production?
Mitochondria
Cellular organelles
Nucleus Endoplasmic reticulum Golgi apparatus Mitochondria Lysosomes Peroxisomes and endosomes
Which of the following organells is directly associated with the synthesis of proteins for secretion?
Rough ER
Endocytosis
Includes Pinocytosis and phagocytosis
- coated pits(with clathrin) with or without receptors
- Form phagoctyic vesicles
