Brainscape's Knowledge GenomeTM

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


See full index

Biology Unit 3 > Homeostasis > Flashcards

Homeostasis Flashcards

1
Q

What is homeostasis?

A

The maintenance of a state of dynamic equilibrium in the body despite fluctuations in internal and external conditions.

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

Why is homeostasis important?

A

To ensure optimum conditions for enzymes and cellular processes in the body.

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

Define Negative feedback :

A

Self-regulatory mechanisms which return the internal environment to the optimum when there is a fluctuation.

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

Define Positive feedback:

A

A fluctuation which triggers changes that result in an even greater deviation from the normal level.

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

What is the set point?

A

A desired value or range of values determined by a coordinator.

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

Describe Effectors:

A

Muscles or glands which enable a response to a stimulus.

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

Describe the role of a coordinator:

A

Coordinates information from the receptors and sends instructions to the effectors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is osmoregulation?

A

The regulation of the water potential of body fluids (e.g blood,tissue fluid,lymph) by the kidney.

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

Why is osmoregulation important?

A

Prevents cells bursting or shrinking when water enters or leaves by osmosis.
Cellular reactions occur in aqueous solution therefore water levels affect conc and rate of reactions in cells

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

Define excretion?

A

The process of removing metabolic waste from an organism.

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

What is the function of the renal artery?

A

Supplies blood to the kidneys

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

What is the function of the renal vein?

A

Takes blood aways from the kidneys

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

What is the function of the ureter?

A

Takes urine to the bladder from the kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of the urethra?

A

Release urine from the bladder, out of the body.

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

Key components of a kidney:

A

Bowman’s Capsule,cortex,renal pyramids,renal pelvis and medulla

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

Where are nephrons found in the kidneys?

A

Part of the nephron is located in the medulla and part in the cortex.

17
Q

Define Ultrafiltration:

A

The removal of small molecules,water and ions from the blood in the glomerulus of the kidney at high pressure

18
Q

Why is there a build-up of pressure in the glomerulus?

A

Afferent arteriole leading into the glomerulus is wider than the efferent arteriole taking blood
from the glomerulus.

19
Q

How are cells of the Bowman’s capsule adapted for ultrafiltration?

A

● Fenestrations between endothelial cells of capillaries

● Fluid can pass between and under folded membrane of podocytes

20
Q

Where does selective reabsorption occur?

A

Proximal convoluted tubule

21
Q

What happens during selective reabsorption?

A

● Useful molecules from glomerular filtrate (glucose, some water, some ions) are reabsorbed into the blood
● Involves membrane transport proteins

22
Q

By what mechanism are amino acids and glucose selectively reabsorbed into the blood?

A

● Secondary active transport

● Uses a co-transport mechanism involving Na+

23
Q

By what mechanism are mineral ions selectively reabsorbed into the blood?

A

Active transport

24
Q

How are filtered proteins (and some urea) selectively reabsorbed into the blood?

A

Via diffusion

25
Q

Describe the loop of Henlé.

A

A loop consisting of a descending limb (dips into the medulla) and ascending limb (rises into the cortex) surrounded by blood capillaries.

26
Q

What is an endocrine gland?

A

A gland of the endocrine system that secrete hormones directly into the bloodstream.

27
Q

How is the concentration and volume of urine controlled?

A

Controlled by the secretion of anti-diuretic hormone (ADH).

28
Q

Explain the role of the hypothalamus in osmoregulation.

A

● Osmoreceptors in hypothalamus detect the concentration of the blood plasma
● Hypothalamus secretes ADH

29
Q

Explain the role of the posterior pituitary gland in osmoregulation.

A

Stores and secretes the ADH produced by the hypothalamus.

30
Q

Describe the effects of kidney failure.

A

● Build-up of toxic waste products (e.g. urea) causes symptoms such
as vomiting
● Fluid accumulation leads to swelling
● Disruption to electrolyte balance can make bones more brittle
● High concentrations of renin may lead to hypertension
● Low concentrations of EPO can lead to anaemia

31
Q

Outline the potential treatments for kidney failure.

A 
● Low protein diet
● Control of blood calcium and potassium levels using medication
● Drugs to lower blood pressure
● Renal dialysis
● Kidney transplant
32
Q

Describe renal dialysis.

A

● Medical procedure that artificially filters the blood
● Relies on a partially permeable membrane between
the patient’s blood and dialysis fluid
● Two types: haemodialysis and peritoneal dialysis.

33
Q

Describe how animal excretory products can differ.

A

● Freshwater animal species excrete ammonia
● Reptiles, birds and insects produce uric acid
● Mammals excrete urea

34
Q

How does the length of the loop of Henlé differ between mammals?

A

● Length of the loop varies depending on the availability of water in the mammal’s environment
● Longer loop in desert animals (e.g. kangaroo rat) to allow greater time for reabsorption of water and salts

35
Q

Describe the process of ultrafiltration:

A

Bowman’s capsule
High Hydrostatic Pressure in G forces small molecules (U,W,G,I) out of capillary fenestrations against O G
Basement membrane filter - Blood cells and large molecules (P) remain in capillary.

36
Q

How are cells in the proximal convoluted tubule adapted for selective reabsorption?

A

MV LSA for Co-T P
Lots M ATP for AT of G into intercellular spaces
Folded Basal Membrane LSA
Tight Junctions stop ReA materials leaking back intol filterate
Peritubular C extend into the M enabling reabsorption of materials

37
Q

Describe what happens in the loop of Henlé.

A 
AT of Na+ and Cl- out of AL
WP of Interstial Fluid D
Movement of water out of DL via O
WP of F D going down D (lowest M,highest AL)
Counter Current Multiplier
38
Q

Describe how ADH affects the reabsorption of water from the kidney tubules.

A

● ADH causes insertion of aquaporins into the plasma membranes
of cells of the DCT and collecting duct
● Increases permeability of the DCT and collecting duct
● More water reabsorbed
● More concentrated urine produced

Biology Unit 3 (4 decks)

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