Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HUBS191 > Principles of Homeostasis > Flashcards

Principles of Homeostasis Flashcards

0
Q

Resting Membrane Potential (RMP)

A

Refers to the fact that the inside of the cell membrane is negatively charge compared to its external surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What happens if the osmolarity of one compartment changes?

A

Water will diffuse by osmosis until equilibrium is restored.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the magnitude of the negativity inside the cell?

A

Typically about -70mV

If outside of membrane is taken as 0mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What causes the RMP?

A

The separation of a small number of oppositely charged ions across the lipid bilayer. (Doesn’t affect conc of ions in ICF and ECF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the major determinant of the RMP?

A

K+ because it is cell membrane is more permeable to it than other ions.
Can ignore other ions for now.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Hypothetical cell has ICF K+ conc of 150mmol/L and ECF K+ conc of 4mmol/L, what happens?

A

When amount of K+ leaving the cell down its conc gradient is balanced by that moving back in due to the electrical gradient we have the RMP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Does the RMP remain constant?

A

Yes for most cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What tissues have a RMP that changes?

A 
Excitable tissues (nerve/muscle) 
Must change to function
Usually via opening/closing specific channels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Physiological significance of RMP?

A

It must change for the nervous system and cardiac muscle to function.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Controlled variable

A

The variable that tries to stay stable.

Eg speed of a car

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Set point (for variable)

A

Target variable for controlled variable

Eg. 100km/h

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Reference (normal) range

A

Values of the controlled variable within acceptable limits.
Eg 90-110km/h
Average 2 s.d. Either side of set point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Variation for homeostasis

A

Values within and between ‘normal’ people

Inter and intra individual variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What causes variation in homeostasis?

A
  • genetic factors give different set points (interindividual variation)
  • variation may occur within an individual (intra individual variation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Variation in response to biological rhythms

A

24hrs blood glucose

Monthly female hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What context needs to be considered for variations in homeostasis?

A

Age/sex/size/time of day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Homeostasis is controlled by

A

Feedback and feed forward control systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Negative feedback

A

Opposes the change in controlled variable and moves back towards the set point

18
Q

Key components of the negative feedback system

A
  1. Sensor
  2. Integrator
  3. Effector
  4. Communication pathways
19
Q

Sensor

A

Monitors actual value of controlled variable.

Can be same as integrator

20
Q

Integrator

A
  • Compares actual and set point values
  • Determined and controls the response
  • Can be the same as sensor
21
Q

Effector

A

Produce response that restores to set point

22
Q

Communication pathways

A

Carry signals between components

23
Q

Physiological communication pathways

A

Neuronal (relies on nerves)

Hormonal

24
Q

Neuronal physiological communication pathways

A
  • fast (up to 100m/s)
  • specific
  • good for rapidly changing conditions
    Where immediate response required to protect tissue from damage or loss of homeostatic control
  • good for brief responses
25
Q

Hormonal physiological communication pathway

A
  • hormones released into blood (or ECF)
  • target cells that have specific receptors for particular hormone
  • good widespread sustained responses
    Eg fluid volume regulation
26
Q

Evaporation

A

Of water from the skin takes heat from the body

27
Q

Radiation

A

Transfer of heat from the surface of one object to another without contact.
Heat radiates from the body to cooler objects.
To the skin from warmer objects.

28
Q

Conduction

A

Transfer of heat to any substance in contact with body

29
Q

Convection

A

Transfer of heat away from the body by movement of heated air or fluid particles.

30
Q

Feed forward

A

Detection/anticipation of external/internal conditions that could alter a controlled variable (or disrupt homeostasis) if action not taken.

31
Q

What role does the integration centre have in feed forward

A

Establishes a future ‘predicted’ value for controlled variable, compares this with the set point and makes anticipatory corrections.
Eg goosebumps/shivering when cold
(Physiological)
- putting more clothes on/seeking shelter if skin cold (behavioural)

32
Q

Positive feedback

A

A response to a stimulus that moves controlled variable even further away from a set point.
- not commonly physiological and most causes harm (detrimental)

33
Q

Physiological positive feedback

A

Where there is a specific end point/purpose:

  • childbirth (uterus expanding)
  • blood clotting (blood cells moving to clot)
34
Q

Diabetes Mellitus:

A

Failing to regulate blood glucose concentration

35
Q

What type of diabetes Mellitus is no insulin produced?

A

Type 1

36
Q

What happens if type 1 diabetes is not treated?

A

Polyuria: large amounts of water lost from body (urine) increased osmolarity
Polydipsia: leads to excessive thirst
Polyphasic: can’t get glucose from blood to cells (energy deprived) excessive hunger

37
Q

Type 2 diabetes Mellitus

A
  • decreased insulin secretion

- hyperglycaemia (but different to type 1) eg less fat breakdown & ketone production

38
Q

Consequences of absolute insulin deficiency (acute)

Type 1 mostly

A
  • hyperglycemia
  • glycosuria
  • polyuria
  • dehydration
  • thirst
  • breakdown of protein and fat
  • ketoacidosis
39
Q

Hyperglycemia

A

High blood glucose

  • inability of most cells to absorb glucose
  • low energy production
  • ice eased output of glucose by liver (body thinking it is being fed)
40
Q

Glycosuria

A

Glucose in the urine

- kidneys can’t absorb all glucose

41
Q

Ketoacidosis

A

Fatty acids metabolised so there are too many

- pH drops

42
Q

Consequences of absolute insulin deficiency

Chronic problems

A
  • cardiovascular disease
  • renal failure
  • retinal damage
  • poor wound healing
  • peripheral nerve damage
  • susceptibility to infection
43
Q

Type 2 diabetes problems

A

Still some insulin production

  • enough to prevent ketoacidosis & limit tissue breakdown
  • not enough to prevent hyperglycemia

HUBS191 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions