EXAM 1 Module 1.2 Fluid Composition and Homeostasis Flashcards
(69 cards)
1
Q
“internal sea” in which cells that make up complex organisms exist in
A
extracellular fluid (ECF)
2
Q
in mammals with a closed vascular system, the ECF fluids are ________ to enable exchange of ____________
A
compartmentalized; nutrients and waste
3
Q
functions of the organ systems are still essential for survival because…
A
- most of the cells are isolated from the external environment
- existence of a stable environment made up of fluids in distinct compartments
- the constant balance between these internal fluid compartments is necessary for the normal functioning of the entire body
4
Q
separates the ICF from the ECF compartment
A
cell membrane/plasma membrane
5
Q
ECF composition is similar to…
A
sea water
6
Q
ICF is _________ in comparison to ECF in composition
A
different (based on sodium, potassium, proteins concentrations)
7
Q
separates the interstitial fluid from the blood plasma
A
capillary wall
8
Q
plasma is _________ in comparison to the interstitial fluid in composition
A
very similar (based on sodium, calcium, potassium concentrations)
9
Q
important in keeping fluid inside the cardiovascular system
A
plasma proteins
10
Q
when there is too much interstitial fluid
A
edema
11
Q
example: finger swelling
A
edema
12
Q
volume of total body water (TBW)
A
60% of body weight
13
Q
volume of intracellular fluid
A
2/3 total body water
14
Q
volume of extracellular fluid
A
1/3 total body water
15
Q
volume of interstitial fluid
A
80% extracellular fluid
16
Q
volume of plasma
A
20% extracellular fluid
17
Q
TBW (water weight) formula
A
(weight) x (0.6)
18
Q
ICF volume formula
A
(TBW) x (2/3)
19
Q
ECF volume formula
A
(TBW) x (1/3)
20
Q
interstitial volume formula
A
(ECF) x (0.8)
21
Q
plasma volume formula
A
(ECF) x (0.2)
22
Q
the relative constancy of the internal environment
A
homeostasis
23
Q
kept within certain pre-set limits
A
homeostatic range
24
Q
homeostasis is a state of…
A
dynamic constancy
25
any variable does not stay rigidly constant, but constantly fluctuates around a normal range;
during healthy conditions, it gets restored to normal;
in disease, this imbalance may be the cause or is difficult to reset
dynamic constancy
26
cells and action potential are very sensitive to and dependent upon the concentrations of sodium, potassium, and other ions in the _______________
interstitial fluid
27
when there is a change in the ECF composition, the body initiates reactions to ____________
correct or minimize that change
28
response to change is mediated using ____________
homeostatic control systems
29
examples of variables mediated by homeostasis
ions (pH)
fluids
blood sugar
body temperature
30
example: response to a fall in body temperature
first, core temperature of the body is continuously sensed by ____________ located in the body
thermoreceptors
30
example: response to a fall in body temperature
second, that temperature information is sent to the ___________ located in the ____________
integrating center; hypothalamus (in the brain)
31
example: response to a fall in body temperature
third, in the integrating center, this body core temperature is continuously compared to the _________
set point
32
set point temperature
normally 37C or 98.6F
33
if the body core temperature has fallen to 36C, the integrating center will produce changes in the ________ to bring the body temperature back up to 37C
effectors
34
biological control system that directly links a stimulus with a response
reflex arc
35
detectable change in the controlled variable
stimulus
36
sensor on which the stimulus acts
senses changes with internal or external environment
receptor
37
homeostatic reflex arc:
first, signal is transmitted from the _________ to the _________
receptor; integrating center (typically in brain or spinal cord)
38
homeostatic reflex arc:
second, signal transmission happens via an ________ pathway
afferent pathway (can be neural or hormonal)
39
homeostatic reflex arc:
third, the integrating center integrates the input from many receptors and sends its response to the _________, via ________ pathways
effectors; efferent
40
decreases the effect of the stimulus, producing negative feedback in a homeostatic control system
response
41
minimizes fluctuations
moves the variable in the opposite direction
negative feedback
42
example: stimulus is decreased body temperature
negative feedback
43
example: stimulus is decreased body temperature
effector: blood vessels in the skin
response: ___________
constriction
44
example: stimulus is decreased body temperature
effector: voluntary muscles
response: ___________
curling into a ball, adding clothes
45
example: stimulus is decreased body temperature
effector: general muscle activity
response: ___________
shivering
46
example: stimulus is decreased body temperature
result: ________ responses return the body temperature closer to its normal value
effector
47
anticipate changes
minimize fluctuations in the variable that is being controlled
can speed up the body’s response
feedforward mechanisms
48
example: thermoreceptors in the skin monitor skin temperature and send this information to the hypothalamus;
when you enter a cold room, the skin temperature will fall before the core temperature falls
feedforward mechanism
49
examples of feedforward mechanisms
- preparation for exercise (initiates sympathetic activation, reduces adrenaline rush)
- olfactory cues (smells) turn on digestive system
50
accelerates a process, leading to an "explosive" system (like an avalanche)
positive feedback
51
positive feedback typically ends with a ____________
major event that stops the process
52
example: the hormonal control of uterus contractions during childbirth (aka Ferguson reflex)
positive feedback
53
positive feedback in childbirth:
stimulus - _________ on the cervix
increased pressure
54
positive feedback in childbirth:
effector - _________ acting on the uterus
oxytocin
55
positive feedback in childbirth:
response - _________ until baby is delivered
contraction and increased pressure
56
examples of positive feedback
- blood clotting (activated platelets adhere to wound site)
- ovulation (estrogen leads to more estrogen release)
- action potential (Na+ entry leading to Na+ channel opening)
- muscle contraction (Ca2+ entry leads to Ca2+ release in the cell)
57
all homeostatic responses rely on _________ between cells to cause a response
communication
58
types of chemical messengers
hormones
neurotransmitters
paracrine agents
autocrine agents
59
chemical messenger secreted by endocrine cells into the bloodstream
hormone
60
chemical messenger released by a neuron to affect a muscle, gland, or nerve cell
neurotransmitter
61
neurotransmitters travel through the _________
synaptic cleft
62
chemical messenger released by a cell that acts on nearby cells
paracrine agent
63
chemical messenger released into the interstitial fluid that acts upon the very cell that secreted it
autocrine agent
64
the characteristic that determines the type of messenger is...
to where it travels
65
the same substance can be a ____________ in one place and a ____________ in a different area of the body
neurotransmitter; hormone
66
the loss or gain of substances from individual response mechanisms when a healthy condition is present (fluids and chemical substances are in safe and controlled range)
homeostatic balance
67
individual reflex responses result in an overall loss of a substance
negative balance
68
individual reflex responses result in an overall gain of a substance
positive balance
