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study cards > Bio U4 > Flashcards

Bio U4 Flashcards

1
Q

Type 2 diabetes

A

Non-insulin dependent
Still produces insulin
With age, response to insulin declines
Level of insulin secreted by B cells decline

Diet in high sugars, obesity and family history

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2
Q

Different ways in which the pancreas acts as endo and exocrine functions

A

Exocrine function of the pancreas j’s manufacturing and releasing digestive enzymes into ducts (lipase/amylase)

Endocrine function is releasing hormones into the blood

Islets of lancer hand have a endocrine function and contains a and B cells. å cells secrete glucagon and B cells secrete insulin into the blood.

Enzymes found in cells surrounding small tubules are released during the exocrine functions of the pancreas. The tubules carry the enzymes to the small intestine

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3
Q

Medulla Oblongata

A

Found at the base if the brain

Coordinates the unconscious functions of the body - breathing and heart rate

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4
Q

Action potentials sent down the accelerator nerve …

A

Increase the heart rate

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5
Q

Action potentials sent down the vagus nerve …

A

Reduce the heart rate

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6
Q

Why do animals need to alter their heart rate

A

Respond to internal stimuli
Prevent fainting due to low blood pressure
Make sure heart rate is high enough to supply body with enough oxygen

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7
Q

Baroreceptors

A

Detect changes in blood pressure

Found in the aorta / vena cava

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8
Q

Chemoreceptors

A

Detect chemical changes

Found in aorta / Oblongata

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9
Q

What is the cardiovascular centre

A

Specific region in the medulla Oblongata that receives sensory inputs about the levels of physical activity/ old CO2 concentration and bloood pressure
Sends nerve impulses to the SAN in the heart to alter the frequency of the excitation waves

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10
Q

Heart response to exercise

A

CO2 levels increase when exercising
Reduces pH in blood
Detected by chemoreceptors
Impulses sent to medulla Oblongata which sends a signal down the accelerator nerve to the SAN for a increase in HR

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11
Q

Heart rate response to adrenaline

A

Adrenaline is secreted in response to stress/injury
Adrenaline binds to the receptors on cardiac muscles
Cardiac muscles contract more frequently and with greater force
HR increases

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12
Q

Heart rate in response to BP

A

Increase in blood pressure is detected by baroreceptors

Impulses are sent to the medulla Oblongata and then via the vagus nerve to the SAN to decrease HR

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13
Q

How do animals increase their chances if survival

A

By responding to changes in their external environment

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14
Q

What is a stimulus

A

A change in internal/external environment

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15
Q

Receptors

A

Detect stimuli (they are specific only detecting one particular stimulus

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16
Q

Sensory receptors

A

Specialised cells that can detect changes in our surroundings

Transducers that concert one form of energy to another

Whatever the stimulus the sensory receptors convert the energy into a form of electrical energy called a nerve impulse

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17
Q

Effectors

A

Cells that bring about a response to a stimulus in order to produce a effect

Effectors can be muscle cells and cells found in glands

18
Q

Sensory Neurons

A

Transmit nerve impulses from receptors to the CNS

Has long dendrone that transmits the impulse to the cell body

Axon carries the impulse from the cell body to the axon terminal where the neurotransmitters are released

19
Q

Motor Neurones

A

Transmit nerve impulses from the CNS to the effectors

Dendrites receive information from the CNS
The electrical impulse travels from the cell body along the axon terminal where the neurotransmitters are released

20
Q

Relay neurones

A

Transmit nerve impulses between sensory and motor neurones

21
Q

What creates and maintains a neurones resting potential

A

Sodium-potassium pump

Voltage gated potassium channels

IN THE NEURONES MEMBRANE

22
Q

What is the potential difference across a neurone membrane

A

-60mV

23
Q

What is a action potential

A

When a neurone is stimulated, other ion channels in the cell membrane called sodium ion channels open

24
Q

What are the sequence of events that occur during the action potential

A 
1 stimulus 
2 depolarisation 
3 repolarisation 
4 hyperpolarisation
5 resting potential
25
Q

Stimulus

A

Excites the neurone cell membrane causing Na+ ion channels to open
Membrane becomes more permeable to sodium so sodium ions diffuse into the neurone down the sodium ion electrochemical gradient
Inside of neurone turns less negative

26
Q

Depolarisation

A

If potential difference reaches the threshold potential (-55mV) voltage gates sodium ion channels open and more sodium ions diffuse into the neurone

27
Q

Repolarisation

A

At a potential difference of +40mV sodium channels close and potassium ion channels open
Membrane is more permeable to potassium so potassium ions diffuse out of the neurone down the potassium ion concentration gradient (membranes starts to get back to resting potential )

28
Q

Hyperpolarisation

A

Potassium ion channels are slow to close resulting in a slight overshoot and too much potassium ions diffuse out of the neurone

Potential difference becomes more negative than the resting potential (-70mV)

29
Q

Resting potential

A

Ion channels are reset
Sodium-potassium pump returns the membrane to it’s resting potential by pumping sodium ions out and potassium ions in

Maintains resting potential until the membrane is exited by another stimulus

30
Q

What is the refractory period

A

During the refractory period

Ion channels are recovering and cannot be made to open

This is a time delay to ensure the action potentials do not overlap, ensuring they are unidirectional

31
Q

What is the all or nothing principle

A

When the threshold potential is reached, the action potential is always generated.

Is threshold isn’t reached, the action potential will not fire.

32
Q

How are local currents created in the cytoplasm if the neurone

A

Opening of sodium ion channels

33
Q

Outline local currents

A

Following a stimulus sodium ions move into the neurone and trigger a action potential

They then diffuse along the axon and cause sodium channels further along the membrane to open

This causes a influx of na+ and another action potential is triggered

34
Q

What is the myelin sheath

A

An insulating layer of fatty material

35
Q

Axon diameter

A

Larger the axon diameter the faster the electrical impulse because there is less resistance

36
Q

Temperature

A

Increase in temperature = increase in electrical impulses

This is because there is more kinetic energy so sodium ions can diffuse quicker into the neurone

If temp continues to increase the protein in the membrane will denature and tertiary structure would change and it wouldn’t be able to function

37
Q

Synaptic Divergence

A

One neurone connects to many neurones

Allows information to be dispersed to many different parts of the body

38
Q

Synaptic divergence

A

Many neurones connect to one neurone

Allows signal to be AMPLIFIED

39
Q

Temporal summation

A

One action potential in the presynaptic neurone does not produce a AP in the post synaptic neurone

Require series of APs in presynaptic neurone

40
Q

Spatial summation

A

Several presynaptic neurones may each contribute to producing an AP in the post synaptic neurone

41
Q

What is SUMMATION

A

The way in which several small action potential changes can combine to produce in larger change in potential different across the membrane

42
Q

Type 1 diabetes

A

Insulin dependent
Starts in childhood
Autoimmune response where the body’s own immune system attacks the B cells
Body cannot manufacture sufficient insulin

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