PHS3341 MIDTERM 1 UPDATED ACTUAL QUESTIONS AND CORRECT ANSWERS

PHS3341 MIDTERM 1 UPDATED ACTUAL QUESTIONS
AND CORRECT ANSWERS

Question:
homeostasis
Answer:
maintains stable internal condition despite external environment

Question:
regulated
(sensed) variable
Answer:
ex: BP, body temp

Question:
non-regulated variable
Answer:
ex: HR, blood hematocrit, T levels

Question:
set point
Answer:
ex: 120/80

Question:
sensor
Answer:
detects regulated variable and transduce stimulus

Question:
control center
Answer:
error detector, integrator

Question:
error detector
Answer:
actual value to set point

Question:
integrator
Answer:
interprets error signal and determines output of effectors ex: neuron/brain region

,Question:
effectors
Answer:
change value of regulated variable ex: cells, tissues, smooth muscle, glands

Question:
homeostatic weaknesses
Answer:
- if lost for one variable, can trigger series of change
- sensors respond within limited range of stimulus values

Question:
negative feedback
Answer:
returns to setpoint

Question:
positive feedback
Answer:
pushes variable away from setpoint

Question:
feed-forward control
Answer:
anticipatory, minimize changes to variables

Question:
ECF
Answer:
extracellular fluid - fluid in blood (plasma) and between cells (ISF, interstital fluid)

Question:
% of plasma and ISF in ECF
Answer:
20-25% plasma, 75-80% ISF

Question:
transports
Answer:
passive and active

Question:
passive
Answer:
no energy input is required

, Question:
mechanisms required for passive transport
Answer:
simple, facilitated diffusion, osmosis

Question:
diffusion
Answer:
movement of molecules from high to low - moves down concen gradient

Question:
factors affecting diffusion rate
Answer:
molecular size, temp, concentration, SA, viscosity

Question:
simple diffusion
Answer:
nonpolar, lipid soluble substances diffuse thru phospholipid bilayer ex: O2, CO2,
sterioid hormones, fatty acids

Question:
net influx
Answer:
(J) = PA (Co - Ci)

Question:
facilitated diffusion
Answer:
larger, non-lipid soluble molecules can cross but only with assistance of carrier
molecules

Question:
1. carrier-mediated
Answer:
hydrophilic molecules (ex. glucose, AA and ions) transported passively down concen
grad by carriers

Question:
2. channel-mediated
Answer:
membrane proteins form channels that allow ions to diffuse across membrane ion
channels show selectivity for some ions (Na and K) - based on channel diameter