Muscles and Homeostasis Flashcards

1
Q

State the three types of muscle in the body

A

smooth
cardiac
skeletal

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2
Q

In an antagonistic muscle pair, which is the agonist and which is the antagonist

A

Agonist - contracting

Antagonist - relaxing

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3
Q

What bundles of cells make up skeletal muscle

A

muscle fibres

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4
Q

What is the cell membrane of muscle fibre called

A

sarcolemma

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5
Q

What does the transverse (T) tubule do

A

help spread electrical impulses through the sarcoplasm so that they reach all parts of the muscle fibre

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6
Q

What is stored in the sarcoplasmic reticulum

A

calcium ions

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7
Q

Why do muscle fibres have lots of mitochondria

A

to provide ATP for muscle contraction

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8
Q

which filaments make up the dark band of a myofibril

A

thick myosin filaments and some overlapping actin filaments

These are called A bands

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9
Q

What is contained in the I bands

A

actin filaments

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10
Q

What gets shorter when muscles contract

A

sarcomere

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11
Q

What two binding sites are present on a myosin head

A

actin binding site

ATP binding site

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12
Q

What allows the myosin head to move back and forth

A

Hinge

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13
Q

at rest, what does tropomyosin do

A

blocks actin from binding to the myosin-actin binding site

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14
Q

When an action potential from a motor neurone stimulates a muscle cell, what is depolarised

A

Sarcolemma. This spreads down T tubules to the sarcoplasmic reticulum

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15
Q

What two things do Ca2+ ions do to allow the formation of a cross bridge

A

bind to tropomyosin, changing its shape and thus preventing it from blocking the binding site. They also activate ATP Hydrolase, releasing energy to cause the myosin head to bend allowing muscle contraction

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16
Q

By what process are Ca2+ ions moved back into the sarcoplasmic reticulum

A

Active transport

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17
Q

Give the equation for the phosphorylation of ADP by PCr

A

ADP+PCr->ATP+Cr

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18
Q

What kind of exercise is the ATP- phosphocreatine system good for

A

Short intense bursts, such as a tennis serve

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19
Q

Is the ATP-phosphocreatine system anaerobic or aerobic

A

Anaerobic

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20
Q

Give two structural differences between slow and fast twitch muscle fibres

A

Slow twitch fibres have lots more mitochondria to supply energy over a long period. They have plentiful blood supply to allow respiration

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21
Q

Why is maintaining a stable homeostatic environment important

A

To ensure enzymes have the optimal environment in which to function

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22
Q

What is the effect of a high temperature on enzyme activity

A

Speed it up, until the point where H-bonds break and the enzyme denatures

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23
Q

Explain the effect on the water potential of the blood in relation to high blood glucose concentration

A

High blood glucose concentration means a low water potential of the blood, so water diffuses out of the ells and into the blood via osmosis. this can cause cells to die

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24
Q

Explain the effect on the water potential of the blood in relation to low blood glucose concentration

A

If blood glucose concentration is low, water potential is high. There won’t be enough glucose for cells to respire effectively

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25
Describe the negative feedback mechanism
The level of a substance is too high or low, receptors detect the change and communicate with the cells via either the nervous or hormonal system to have the effectors respond (the) bring the change back to normal levels
26
Why does negative feedback only function within certain limits
If a change Is too big, the effectors cannot counteract the change
27
When does blood glucose concentration rise and fall
Rises after eating, falls when exercising
28
Which cells in the islet of Langerhans secrete each hormone
Alpha cells secrete glucagon beta cells secrete insulin
29
give the reactions for Glycogenesis
Glucose->Glycogen-activated by insulin
30
give the reactions for Gluconeogenesis
Glycerol/Amino Acids - >Glucose - Activated by glucagon
31
give the reactions for Glycogenolysis
Glycogen->Glucose - Activated by glucagon
32
Why are hormonal responses slower than nervous responses
Hormones must travel through the blood
33
When the pancreas detects high blood glucose concentration, which hormone secretion is stopped
Glucagon secretion is stopped
34
When insulin binds to receptors on muscle cell membranes what happens
They become more permeable to glucose as vesicles with GLUT4 proteins fuse with the cell membrane
35
To what cells does glucagon bind
Receptors
36
Where is adrenalin secreted from
Adrenal glands
37
When is adrenalin secreted
Low concentration of glucose in blood when stressed, when exercising
38
What process is inhibited by adrenalin
Glycogenesis
39
Outline the secondary messenger model
A hormone binds to receptors on the outside of cells. This activates an enzyme inside of the cell which produces a chemical known as a secondary messenger. This allows non lipid soluble hormones to effect the inside of cells
40
Which two hormones are secondary messengers
Adrenalin | Glucagon
41
What enzyme is activated when these 2 secondary hormones (adrenalin and glucagon) bind to their receptors
Adenylate cyclase
42
In the secondary messenger model What is ATP then converted to once the enzyme Adenylate cyclise is activated
Cyclic AMP (cAMP)
43
Once ATP is converted into cAMP What enzyme does this activate
Protein kinase A which breaks down glycogen to glucose
44
Which type of diabetes is acquired later in life and is linked to obesity
Type 2
45
What cells does the immune system attack in type 1 diabetes
Beta cells in the islets of Langerhans
46
How can people take steps to reduce their risk of developing diabetes
Exercise | Eat less sugar
47
How do type 1 diabetics control insulin levels
Insulin pens | Controlling diet
48
Define osmoregulation
Regulating the water levels of the blood
49
What cells in the hypothalamus monitor the water potential of the blood
Osmoreceptors
50
When water potential of the blood is low, what hormone is released into the blood
ADH (antidiuretic hormone)
51
What gland releases this hormone (ADH)
Posterior pituitary gland
52
Which cells become more permeable to water because of this hormone (ADH) binding to them
cells in the walls of the DCT and collecting duct
53
What are the substances that enter the Bowman's Capsule known as
Glomerular filtrate
54
In selective reabsorption, where do useful substances pass from and to
They leave the tubules of nephrons and enter the capillary network wrapped around them
55
Where in the body is the medulla
the kidneys
56
Which filaments make up the light band of the myofibril
Light bands contain thin actin filaments | These are called I bands
57
What is the M line
It is the middle of the myosin filaments
58
What is the H zone
The H zone is around the M line and only contains myosin filaments
59
What is the sarcolemma
The cell membrane of muscle fibre cells
60
What is the sarcoplasm
A muscle cell’s cytoplasm
61
What is the sarcoplasm is recticulum
Membrane bound sacs around the myofibrils which release calcium ions for muscle contraction
62
What is the sarcomere
The smallest functional unit of a skeletal muscle fibre