Lecture 1-Exam 1 Flashcards
Organ systems designed to regulate body’s internal environment. What is this called?
HOMEOSTASIS: The ability to maintain a relative consistency in the chemical and physical environment
surrounding the cells of our body, in the face of a variable external environment
NEUROENDOCRINE SYSTEM provides what?
Provides a communication network to tissues and organs
What are the different regulatory systems?
- Negative feedback
- Positive feedback
- Feed forward
What is the thermorugation when cold and hot?
What is the reguation of BP?
What is the reguation of child birth?
What is the feed-forward reflexes?
Are not loops, but serve to prepare the body for upcoming changes or events
What is the example of feed-forward?
The gastrocolic reflex causes an increase in large intestine motility in response to food in the stomach “prepares” the large intesting for incoming food
What can happen in order to help maintain blood volume during hemorrhage?
Fluid can move freely from the interstitial to plasma compartments and helps to maintain blood volume during hemorrhage
- Because approximately 80% of the ECF is interstitial fluid and 20% is blood plasma, how does the ECF and plamsa volume decreases?
- What about the reverse?
- Because approximately 80% of the ECF is interstitial fluid and 20% is blood plasma, a hemorrhaging patient must lose about 5 L of ECF before the plasma volume is decreased by 1 L.
- The reverse is also true; to replace 1 L of plasma volume, approximately 5 L of intravascular isotonic saline must be infused
How much water in each population?
– Infants: 73% or more
– Adult males: ~60% water
– Adult females: ~50% water
– Old age: declines to ~45%
What does interstitial fluid include?
Water continuously exchanges between what?
- Intersitital fluid also includes lymph, CSF, synovial fluid, aqueous and vitreous humor (eyes), pleural, peritoneal, and pericardial fluids
- Water continuosly exchanges between fluid compartments
What are the the components of the mosaic model of plasma membrane?
What are receptors, enzymes, Channel, gated channel, cell-identity marker, cell-adhesion molecule (CAM)
What are tight junctions and what are proteins involved?
- Prevent fluids and most molecules from moving between cells
- Interlocking junctional proteins
- What are desmosomes?
- What are the proteins?
- “Rivets” that anchor cells together
- Intermediate filament (keratin) and linker glycoproteins (cadherins)
- What are gap junctions?
- What does it allow?
- What does it consist of?
- Gap Junctions: Transmembrane proteins form pores that allow small molecules to pass from cell to cell
- Allows spread of ions between cardiac or smooth muscles cells
- Connexons
What are examples of extensions of plasma membrane?
- Microvilli
- Flagella
- Pseudopods
- Cilia
Microvilli:
* Purpose?
* Best developed in cells specialized in what?
* Some microvilli contains what?
- Gives 15 to 40 times more surface area
- Best developed in cells specialized in absorption
* On some absorptive cells very dense
* Appear as a fringe “brush border” - Some microvilli contain actin filaments that are tugged toward center of cell to milk absorbed contents into cell
Flagella:
* What is it?
* What type of structure?
* Movement is what?
- tail of a sperm
- only functional flagellum in humans
- whip-like structure
- movement is undulating, snake-like
Pseudopods:
* What it is?
* What can it be used for?
- continually changing extensions of the cell that vary in shape and size
- can be used for cellular locomotion, capturing foreign particles
What is Cilia (general)
hairlike processes 7–10 μm long
Nonmotile cilium:
* Found where?
* what is it used for?
* Helps with what?
* Found on?
- found on nearly every cell
- “Antenna” for monitoring nearby conditions
- Helps with balance in inner ear; light detection in retina
- Found on sensory cells of nose
Motile cilia:
* Found where?
* How many?
* Beats how?
* Power stokes followed by what?
- respiratory tract, uterine tubes, ventricles of brain, ducts of testes
- 50 to 200 on each cell
- Beat in waves sweeping material across a surface in one direction
- Power strokes followed by recovery strokes
What is the normal physiology of cilia?
- Cilia beat freely within a saline layer at cell surface
* Chloride pumps pump Cl- into ECF
* Na+ and H2O follow - Mucus floats on top of saline layer
- What is a Ciliopathies?
- What is an example?
- defects in structure and function of cilia
- e.g. Cystic fibrosis: hereditary disease in which cells make chloride pumps, but fail to install pumps in plasma membrane. Chloride pumps fail to create adequate saline layer on cell surface. Thick mucus plugs pancreatic ducts and respiratory tract. Inadequate digestion of nutrients and absorption of oxygen. Chronic respiratory infections. Life expectancy of 30.
What inserts aquaporin?
ADH-> distal+collecting duct
Most water moves across membranes via a protein called what?
Aquaporin
transmembrane
What is the difference between simple diffusion and carrier-mediated transport?
Facilitated diffusion involves what?
Ion channels:
* Integral membrane proteins facilitate diffusion of solutes across the plasma membrane.
What are the three types of ion channels?
Non-gated ion channels
* like membrane pores; always open
Voltage-gated ion channels
* open when the membrane potential changes beyond a certain threshold value.
Ligand-gated ion channels
* cannot open unless they first bind to a specific agonist.
Facilitated Diffusion – Carrier-mediated involve?
Carrier-mediated transport moves a range of ions and organic solutes passively across membranes.
What are the types of active transport proteins?
i. Calcium pumps
ii. The H+/K+-ATPase
iii. Proton pumps or H+-ATPases (GERD)
iv. ATP-binding cassette (ABC) transporters
v. Organic anion transporting polypeptides (OATPs)
vi. F-typeATPases
- The action of sodium pumps accounts for what?
- What does it help to create?
- The action of sodium pumps accounts for high Na+ concentration in ECF and high K+ concentration in ICF.
- Helps to create Resting Membrane Potential in cells.
3 Na out and 2 K in