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Biology M5 > 14) Communication and Homeostasis > Flashcards

14) Communication and Homeostasis Flashcards

(51 cards)

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1
Q

Why do animals need to respond to their environment

A

Increase chance on survival

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2
Q

How does communications occur between adjacent and distant cells

A

-Cell signaling

In nervous system , secrete neurotransmiters
In hormonal system , secrete hormones

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3
Q

Define homeostasis

A

Maintaining internal body coditions within constant limits

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4
Q

Why is it vital maintaining homeostasis

A

To allow cells to function normaly and stop them being damaged

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5
Q

Why is it important to maintain
Temperature
Glucose

A

1) Temperature affects enzyne activity , and they control the rate of metabolic reactions

2)So there is enough available for respiration

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6
Q

What is negative feedback

A

Mechanism where the body restpres level to normaal

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7
Q

what is positive feedback?
Give eg.

A

Amplifies the change , increase the level away from the normal level

eg. Platelets

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8
Q

Why is positive feedback not involved in homeostasis

A

It doesn’t keep internal environment constant

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9
Q

What is the CNA

A

The brain and spinal chord

Process information and decides what to do about it

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10
Q

What is a transducer

A

Converts one form of energy into another

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11
Q

What is a potential difference

A

Where there is a difference in charge between inside and outside of the cell

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12
Q

What causes a change in potential difference>

A

Cell membrane becomes excited, more permeable
allow more ions in and out of cell

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13
Q

What is the change in potential difference called?

A

Generator potential

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14
Q

Describe how pacinian corpuscles work

A

Mechanoreceptors - detect pressure and vibrations

Found in skin , contain end of sensory neurone.

When is stimulated , lamellae is deformed and cause deformation of stretch-mediated sodium channel.
Sodium ions channel open and sodium ions diffuse into the cell , creating a generator potential .
WHen generator potential reach a limit, it triggers an action potential

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15
Q

Whaat is the structure of a sensory neurone

A

Short dendrites
one long dendron
receptor to cell body
short axon carfy impulse from cell body to cns

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16
Q

Describe the structure of the motor neurone

A

Many short dendrites
Impulse from CNA to cell body
1 long axon
Cell body to effector cell

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17
Q

Describe the structure of a relay neurone

A

Many short dendrites
carry nerve from sensory to cell body
1 axon carry impulse from cell body to motorneurone

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18
Q

What is a neurone’s resting state

A

the outside of membrane is postively charges than the inside

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19
Q

What is the value of resting potential

A

-70

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20
Q

what created and mantain restinig potential

A

SOdium-potassium pumps
potassium ion channels

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20
Q

what created and mantain restinig potential

Study These Flashcards
A

SOdium-potassium pumps
potassium ion channels

21
Q

What is the function of sodium potassium pumps

Study These Flashcards
A

Move sodium ions out ,so they cannot diffuse back in.
Creates an electrochemical gradient

Move potassium ions into neurone . permeable to potassium so able to diffuse back out

22
Q

What happens to the cell membrane when there is a stimulus

Study These Flashcards
A

Excites neurone
sodium ions channel open
sodium ions diffuse in down electrochemical grad
Inside is less negative

23
Q

What happens in cell membrane when depolarisation occur

Study These Flashcards
A

when potential difference reach the threshhold (-55mv)
Voltage-gated sodium channels open
more sodium ions diffuse in
eg. of positive feedback

24
What happens in cell membrane when repolarisation occurs
Potential difference of +30mv Sodium ions close Voltage-gate potassium ions open Permeable to potassium so ions move out back to resting potential
25
What happens to cell membrane when hyperpolarisation occurs
Potassium ions close too slowly becomes more negative than resting potential
26
what happens to cell membrane when at resting potential
sodium-potassium pump returns membrane to resting potention and maintain until membrane's excited by another stimulus
27
Why cannot the cell membrane be excited again
ion channels are recovering and can't be mmade to open . Refractory period
28
Describe why and how action potentials go faster in myelinated neurones
Myelin sheath - electrical insulator High number of sodium ion channels at Nodes of ranvier Depolarisation occurs at the nodes of ranvier Hence allows saltatory conduction and is fasr non-mylenated => slower
29
What happens when an action potential triggers calcium influx
AP arrive at synaptic knob of presynaptic neurone Stimulate calcium ion channels to open Ca ions diffuse into synaptic knobe
30
What does the release of calcium ions cause
Cause synaptic vesicles to move into presynapti membrane fuse to presynapticc membrane release neurotransmitter into synaptic cleft by exocytosis
31
How does the neurotransmitter trigger an AP on post-synaptic neurone
Bind to specific receptors of post-synaptic membrane cause sodium ions to open influc of sodium ions cause depolarisation neurotransmitter removed from synaptic cleft so response don't keep happening
32
What is an excitatory synapse
neurotransmitter depolarise post-synaptic membrane make an AP
33
What is an inhibitory synapse
Neurotransmitter hyperpolarise post-synaptic membrane preventing AP
34
What is a synaptic divergence
one neurone connect to many neurones
35
What is synaptic convergence
When many neurones connect to one neurone , info can be amplified
36
What is spatial summation
Many neurones release excitatory neurotransmiters to a single neurone.
37
What is temporal summation
2 or more impulses arrive right after eachother on the same neurne
38
How does hormones bind to receptors and trigger second messenger
Hormone binds to receptor and actives enzyme in cell membrane Catalyses a signalling molecule ( known and secondary messenger ) activate cascare inside the cell
39
What happens when adrenaline acts as a first messenger
binds to cell membrane activates adenylyl cyclase cause production of secondary messenger - cAMP from ATP
40
What happens in the Adrenal cortex
Secrete steroid hormones **Cortisol + aldosterone** breakdown proteins + fats into glucose Inc blood volume + pressure supress immune system
41
what happens in the Adrenal Medulla
Protein hormones **adrenaline + noradrenaline ** SHort term inc heart/ breathing rate glycogen-> glucose Blood diverted to brain and musckes
42
What hormone do alpha cells secrete (pink cells )
glucagon
43
What hormone do Beta cells screte (purple cells)
insulin
44
Describe how **Ectotherms** control temperature
Control by changing their behaviour Internal temp depends on external temp Activity level depends on external temp Variable metabolic rate generate little heat
45
Describe how **Endotherms**
Control by homeostasis activity level independent when temp is wihtin limits Constantly high metabolic rate so generate a lot of heat
46
Summarise Type 1 Diabetes
No insulin is produced Auto-immune disease Destroy Beta Cells Kidneys are unable to reabsorb glucose
47
How can we treat Type 1 Diabetes
Insulin therapy - REgular injections , insulin pump -ISlet cell transplantation -Diet , regular excersise
48
Summarise Type 2 Diabters
Beta cells don't produce enough insulin or body cannot respond to insulin Often linked to obesity
49
How can we treat type 2 diabetes
manage lifestyle changes Medication Insulin therapy
50
Why is using GM bacteria to produce insulin better?
CHeaper Larger quantities can be made Less likely to trigger an allergic response

Biology M5 (6 decks)

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