hormones and homeostasis Flashcards

1
Q

what is a hormone

A

chemical substance produced by one of 8 endocrine glands, carried by blood, and altering the activity of one or more target organs

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2
Q

what does the pituitary gland do and secrete

A

most of the hormones the pituitary glands secrete are stimulants for other glands to secrete their hormones:
Produces:
FSH
GH
Luteinizing Hormone - stimulates ovulation in females and testosterone production in males.
Thyroid-stimulating hormone - helps manage metabolism, energy levels and nervous system

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3
Q

what does FSH do and where is it produced

A

produced in the pituitary gland:
FSH (follicle stimulating hormone) stimulates sperm production in male babies and stimulates the ovaries to stimulate estrogen, which helps in egg development in females.

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4
Q

what does the growth hormone do and where is it produced

A

produced in the pituitary gland:
helps children grow and adults strengthen their muscles and bones

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5
Q

what is the luteinising hormone and where is it secreted

A

secreted in the pituitary gland:
stimulates ovulation in females and testosterone production in males

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6
Q

what is a thyroid stimulating hormone and where is it produced

A

produced in the pituitary gland:
as the name suggests the hormone stimulates thyroids to create thyroxine, also helps manage metabolism, energy levels and nervous system

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7
Q

what is the the thyroid gland and what does it do

A

the thyroid gland produces thyroxine
thyroxine increases the metabolic rate and hence regulating growth and development.

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8
Q

what are the pancreas and what do they do

A

the pancrease secrete many digestive enzymes (amylase, trypsin, lipase) but also play a major role in blood glucose level maintainence.

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9
Q

what is insulin

A

insulin is a hormone that is produced by the pancreas.
insulin acts in response to the blood glucose being too high. Insulin promotes glucose –> glycogen which reduces blood sugar levels.
glucose to glycogen conversion occurs in the liver and glucose once converted to glycogen is stored in the liver and muscles.
Inslulin is produced by beta cells

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10
Q

what is glucagon

A

produced by the pancreas, glucagon acts in response to the blood glucose level being too low.
glucagon promotes glycogen —> glucose which increases the glucose level in the blood.
glucagon is produced by alpha cells

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11
Q

what is the adrenal gland and what does it do

A

the adrenal gland produces adrenaline.

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12
Q

what is adrenaline and where is it produced

A

adrenaline is a hormone which is secreted in fight or flight situations.
major part of the sympathetic nervous system.
adrenaline stimulates increase in metabolism, heart rate, respiration, pupil dilation and blood glucose.

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13
Q

what is noradrenaline

A

noradrenaline is the main NEUROTRANSMITTER of the sympathetic nerves in the cardiovascular system. Noradrenaline can constrict blood vessels increasing blood pressure.

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14
Q

what is adrenaline used to treat

A

asthma attacks
cardiac arrest

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15
Q

what is noradrenaline used to treat

A

ADHD
septic shock

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16
Q

what are the testes and what do they do

A

testes produce testosterone (male sex hormone)

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17
Q

what are the ovaries and what do they do

A

produce estrogen (female sex hormone)

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18
Q

why does adrenaline increase pulse and breathing rate

A

so that in fight or flight situations glucose and oxygen can be delivered easily to the muscles

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19
Q

why does adrenaline increase blood glucose

A

for increased respiration in muscle cells

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20
Q

why does adrenaline dilate the pupils

A

so that more information can be processed by the brain

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21
Q

what is homeostasis

A

maintainence of a constant internal environment

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22
Q

what are the “internal environments” that is being referred to

A

Temperature
blood glucose concentration
water concentration
blood pressure

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23
Q

what is negative feedback

A

Negative feedback occurs when conditions change from the ideal or set point and returns conditions to this set point

24
Q

how does negative feedback work

A

if the level of something rises, control systems are switched on to reduce it again
if the level of something falls, control systems are switched on to raise it again

25
what is the problem in patients with type-1 diabetes and how is it treated.
blood glucose is far too high as insulin secreting cells in the pancreas are not secreting enough insulin. treated with insulin shots
26
how does the body regulate heat, when there is an increase in body temp
increase in body temp -> thermoreceptors in the hypothalamus and skin detect change -> increased sweating, vasodilation, hairs lie flat on skin -> decrease in body temp to normal temp (37C)
27
how does the body regulate heat, when there is a decrease in body temperature
decrease in body temp -> thermoreceptors in the hypothalamus and skin detect change -> vasoconstriction, shivering, hair on skin erect -> increase in body temp to regular temp (37C)
28
how does sweat help cool the body
sweat secreted by sweat glands evaporates off the skins surface leaving a cooling effect on the skin
29
how does shivering help heat up the body
skeletal muscles contract rapidly, the contractions need energy from respiration some of this energy is transferred as heat.
30
what is the effect of strenuous exercise on the volume of water lost by the skin and the kidneys
volume of water lost by the skin:- increases volume of water lost by the kidney:- decreases
31
why does vasoconstriction make us feel warmer
capilaries get narrower, less blood flow to the surface of the skin, less heat lost by radiaton from blood travel
32
why does vasodilation make us feel colder
arterioles relax, more blood is flown to the surface of the skin, more heat is lost by radiation making us feel cooler.
33
what is gravitropism +ve response -ve response
growth in plants towards/away from gravity positive response: growth towars gravity (towards the ground) negative response: growth away from gravity (away from the ground)
34
what is phototropism +ve response -ve response
growth towards/away from light positive response: growth towards light (towards shoot) negative response: growth away from light (towards root)
35
what are shoots photopic and gravitropic
positively phototropic negatively gravitropic
36
what is a clinostat
a device that revolves slowly and repeatedly so the shoots are evenly exposed to light. Allows all the sides of the seedlings to get an equal amount of light so they dont curve towards the light but grow straight up
37
What is auxin
growth hormone in plants which controls the direction of the plant growth
38
how do plants control their growth
chemically
39
where is auxin made and how does it spread
in the tips of growing stems and roots, diffuses to the other parts of the stem/roots spreading from high concentration to low concentration
40
what does auxin stimulate
auxin stimulates the cell behind the tip to elongate. the more auxin present the more they will grow
41
How does auxin affect phototropism
if light is shone all around the tip then auxin is distributed evenly and equally and the cells in the meristem grow at the same rate. when light shines on the shoot predominantly from one side then the auxin produced in the tip concentrates on the shaded side (side with no light), making cells on the shaded side elongate and grow faster than the side facing the light.
42
how does auxin affect gravitropism
Auxin collects on the lower side of the plant making it grow faster than the upper side causing it to curve upwards
43
where does auxin collect in plants exposed to light and plants under the force of gravity how does the plant grow accordingly
gravity: bottom. grows upwards light: shaded side. grows towards the light
44
in which organ do the breakdown of hormones first appear
liver
45
which target organ releases glucose into the blood as a result of adrenaline
liver
46
what part of the eye prevents total internal reflection
choroid
47
explain how a decrease in water potential of the blood may damage the red blood cells
water diffuses out of the rbc through a partially permeable membrane down the water potential gradient
48
which part of the brain is key in maintaining homeostasis
hypothalamus
49
why must internal body temperatures remain below 37 degrees C
If body temperature increases over this temperature, enzymes will denature and become less effective at catalysing reactions such as respiration
50
Describe how the nervous system coordinates the response of the skin to cold weather.
change in temperature acts as a stimulus thermo receptors in the hypothalamus and skin detect change electric impulse travels through sensory neurone to brain relay neurone to motor neurone to effector (eg arteriole)
51
Explain how negative feedback is involved in the control of body temperature.
change in temperature is detected and acts as a stimulus to keep temperature constant corrective action by body is taken body temperature returns back to normal (37 deg C) homeostasis is maintained
52
Explain how the liver lowers blood glucose concentration when it is too high.
responds to insulin (from the pancreas) increased uptake of glucose glucose converted to glycogen insoluble glycogen is stored in the liver
53
Explain how an increase in glucose concentration is controlled in the body.
pancreas detect increase in glucose concentration pancreas secrete insulin liver converts glucose to glycogen stores in liver homeostasis maintained
54
Explain how a decrease in water potential of the blood may damage red blood cells.
water, diffuses out of red blood cells through partially permeable membrane by osmosis down water potential gradient red cells decrease in volume
55
The organs of the human body are coordinated by the nervous system. Outline one other way in which these organs are coordinated.
hormones secreted in the blood stimulate target organ