homeostatis Flashcards
1
Q
Define homeostasis
A
maintaining a constant internal conditions inside the body in response to internal or external changes
2
Q
What is the nervous system?
A
a network of nerve cells and fibres which transmits nerve impulses between parts of the body
3
Q
What is the endocrive system?
A
a collection of glands that produce hormones that regulate metabolism, growth, sexual function, sleep, reproduction, mood etc.
4
Q
What are the nervous system components?
A
brain, spinal cord, nerves
5
Q
What is a stimulus?
A
A change in your enviournment which you need to react to, for example light, sound touch, pain, pressure etc.
6
Q
What do sensory neurones do?
A
carry signals from receptors to the brain
7
Q
What do relay neurones do?
A
carry messages from one part of the CNS to another
8
Q
What do motor neurones do?
A
carry signals from CNS to effectors
9
Q
What is the central nervous system?
A
CNS= brain and spinal cord
10
Q
What is the peripheral nervous system?
A
PNS= nerves
11
Q
What are sense organs?
A
receptors that detect stimal: eyes, nose, ears etc.
12
Q
What is the Synapse?
A
the tiny gap between 2 meeting neurones
13
Q
What are the main stages of a reflex arc?
A
stimulus->receptor->sensory neuron->relay neuron->motor neuron-> effector->response.
14
Q
What is the optic nerve function?
A
connects and sends messages from the eye to the brain
15
Q
What is the cornea function?
A
allows light rays enter the eye
16
Q
What is the iris function?
A
Contrasts size of the pupil, helping regulate entry
17
Q
What is the pupil function?
A
allows light to pass through the iris
18
Q
What is the ciliary muscle function?
A
alters the thickness of the lens through contraction
19
Q
What is the sclera function?
A
protects the delicate parts of the inside of the eye
20
Q
What is the suspensory ligaments function?
A
hold the lens in position and alters its shape
21
Q
What is the retinas function?
A
contains light sensitive cells
22
Q
What is the blind spot function?
A
point at which optic nerve leaves the eye.
23
Q
How is the temperature of the body monitored?
A
controlled by the thermoregulatory centre, skin has temperature receptors
24
Q
What is the thermoregulatory centre?
A
contained in the hypothalamus in the brain, contains receptors sensitive to the temperature of the blood
25
How does the body respond if body temperature becomes too high?
Vasodilation, sweat production, which both transfer energy from skin to the environment, resulting in a cooling effect.
26
How does the body respond if the body temperature is too low?
Vasoconstriction, and shivering (involuntary contraction and relaxation of muscles which releases energy from glucose) starts
27
What happens to excess protein in a diet?
The excess amino acids produced from digesting proteins are transported to the liver from the small intestine
28
how does the kidneys function to maintain water balance in the body?
Producing urine. The urine is taken from the kidneys to the bladder by the ureters. The bladder stores the urine until it is convenient to expel it from the body.
29
2 ways kidney failure can be treated
Kidney dialysis (Medical treatment in which blood is removed from the body and filtered before being returned) or organ transplant
30
response of plants to light
phototropism
31
response of plants to gravity
geotropism
32
3 ways auxins are used in agriculture and horticulture
as weed killers.
as rooting powders.
for promoting growth in tissue culture.
33
role of ethene in plants
controls cell division during plant growth.
34
how is ethene used in the food industry?
to speed up the ripening process, after fruits have been transported
35
what can ethene cause in plants
shedding of leaves
36
role of gibberlins in plants
help the plants to grow taller
37
3 ways gibberellins are used in agriculture and horticulture
end seed dormancy.
promote flowering.
increase fruit size.
38
function of medulla
unconscious control; breathing, heart rate etc.
39
function of cerebral cortex
essential functions; memory, learning, thinking etc.
40
function of cerebellum
coordinating movement and balance
41
function of pituitary gland
regulates growth, metabolism, and reproduction through the hormones that it produces
42
why is it difficult to investigate brain function?
Ethical issues, accidental and unremovable damage, high risk.
43
why is it difficult to treat brain damage and disease?
The brain is delicate, complex, and not well understood
44
techniques used to map some areas of the brain to their functions
by electrically stimulating areas of the brain (certain parts of the brain are stimulated and then the effect is observed) and MRI scans (monitor electrical activity during certain scenarios.)
45
difference in pupil size in bright and dim light.
in bright light, circular muscles contract and radial muscles relax to make the pupil smaller. In dim light the opposite occurs, circular muscles relax and radial muscles contract in order to make the pupil wider and allow more light into the eye.
46
name of process that changes shape of lens to focus on near/distant objects
accomadation
47
to focus on near objects
the lens becomes thicker, this allows the light rays to refract (bend)
48
to focus on distant objects
the lens is pulled thin, this allows the light rays to refract slightly.
49
why are reflexes important?
minimise damage to the body from potentially harmful conditions
50
which hormone is produced by the adrenal gland
adrenaline
51
when is adrenaline produced?
in times of fear/stress
52
how does the endocrine system produce a response to a stimulus
Endocrine glands make chemicals called hormones and pass them straight into the bloodstream
53
where is thyroxide produced?
thyroid gland
54
what is thyroxides function?
regulates metabolism and helps control the body's energy production
55
how is level of thyroxide controlled?
a feedback loop system that involves the hypothalamus in the brain and the pituitary and thyroid glands.
56
what causes type 1 diabetes?
a disorder in which the pancreas fails to produce enough insulin
57
when does type 1 diabetes usually start
early age
58
how is type 1 diabetes treated
insulin injection, pump.
59
what causes type 2 diabetes?
the person's body cells no longer respond to insulin produced by the pancreas
60
risk factors for people with type 2 diabetes?
inactivity, obesity, hertiage
61
how is type 2 diabetes treated?
changing eating/exercising habits, cholestrol pills/medication
62
what is the main reproductive hormone in females?
oestrogen
63
what is ovulation
The egg is released due to high LH. Oestrogen increases the amount of LH, and decreases the amount of FSH. This causes the egg to be released from the follicle
64
what is the main male reproductive hormone
testosterone
65
what does testosterone do?
stimulates sperm production.
66
role of FSH
stimulates oestrogen production and the growth of follicles (egg-sacs) in the ovary
67
role of LH
stimulates the release of the egg
68
role of oestrogen?
causes the development of the thick, spongy uterus lining
69
role of progesterone?
maintains the uterus lining
70
how do oral contraceptives work?
Contains both oestrogen and progesterone. By taking it every day, enough oestrogen builds up in the female body to inhibit the production of FSH so that no eggs mature.
71
how do injection, implant or skin patch of progesterone work?
Contraceptive injections, implants or skin patches contain slow release progesterone to inhibit the maturation and release of eggs.
72
how do barrier methods in contraception work?
physically stopping the sperm from fertilising the egg
73
how do intrauterine devices in contraception work?
by stopping the implantation of the embryo into the womb by releasing copper
74
how do spermicidal agents work?
kill sperm cells
75
how does abstienence work as a contraceptive?
two people don't have sex, sperm can't fertilize an egg and there's no possibility of pregnancy
76
how do surgical methods work as a contraceptive?
the surgeon puts clips on the fallopian tubes to block the sperm and egg from meeting.
77
how can artificial hormones be used to treat infertility?
FSH & LH are given to stimulate the growth of lots of eggs
78
process of ivf
IVF involves giving a mother FSH and LH to stimulate the maturation of several eggs. The eggs are collected from the mother and fertilised by sperm from the father in a dish in the laboratory. The fertilised eggs develop into embryos.
79
3 disadvantage of ivf
emotionally stressful, possibility of multiple births, success rates aren't very high
80
3 advantage of ivf
It allows people to have babies of their own, . It has a safe track record and has been used since 1978. The embryos can be screened for genetic diseases
81
what is stage 1 menstruation cycle
days 1-4 The uterus lining breaks down, resulting in a ‘period’.
82
what is stage 2 menstruation cycle
days 4-14 The uterus lining starts to build up again into a thick, spongy layer full of blood vessels.
83
what is stage 3 menstruation cycle
day 14 Ovulation happens. This is when an egg is released from one of the ovaries.
84
what is stage 4 menstruation cycle
day 15-28 The uterus lining is maintained, which means that it is now ready for the arrival of a fertilised egg (which will eventually grow into a baby). If no fertilised egg is attached to the uterus lining, the lining breaks down and the cycle begins again.
85
what is the combined pill
both oestrogen/progesterone
86
what is progesterone pill
produces thick mucus, difficult for sperm to penetrate, inhibits release fsh
87
what factors disrupt water balance
exhalation- water in lungs; sweating- water, urea, minerals; illness-dehydration due to low blood water concentration
eating too much salt- blood ion concentration increased
88
what do kidneys control
water and ion levels
89
why must ion level be relatively constant
to maintain osmosis and diffusion within the body
90
why does urea need to be removed
it is toxic and if it is in the bloodstream it can damage cells and tissues
91
when is urea formed
when the digestion of proteins is in excess of too many amino acids which can not be stored in the body
92
what is deamination
in the liver amino acids undergo this process and the waste product is ammonia which is then converted to urea which excretes the body as urine
93
what are nephrons
each kidney contains million of them, 2 stages of urine production occur inside these
94
what is ultrafiltration
blood filtered and all water, urea and salts move into nephron, blood cells and proteins remain in the blood as they are too big to move across capillary walls
95
what is selective reabsorption
useful substances, including some water are reabsorbed from the tubule back into the bloodstream, leaving urea, excess salts and excess water and this mixture forms urine which travels to the bladder to be excreted
96
what is the volume of water monitored by
the hypothalamus
97
what happens to the body when there is too little water in the blood
hypothalamus triggers pituitary gland to release ADH, this increases permeability of kidney tubules so more water is absorbed into bloodstream, results in small volume of concentrated urine
98
what happens to the body when there is too much water in the blood
hypothalamus triggers pituitary gland to stop release of ADH, this reduces permeability of kidney tubules, so less water is absorbed into bloodstream, results in large volume of dilute urine
99
why might patients have to have kidney dialysis
if their kidneys cannot keep concentrations of urea and salt at optimum level to ensure tissue damage does not occur
100
how does kidney dialysis work
patients blood passes over a partially permeable membrane in the machine that is designed to replicate the kidney tubules. there is dialysis fluid on the other side. a concentration gradient occurs
101
disadvantages of kidney dialysis
lasts 3-4 hours and is needed 3 times a week, increases chance of blood clots and infections, expensive
102
advantages of kidney dialysis
life-saving, gives patient more time to find kidney donor
103
advantages of kidney transplants
cheaper than dialysis in long run, less time consuming after surgery
104
disadvantages of kidney transplants
kidney may be rejected, long waiting lists, may have to take immunosuppresant drugs which increases risk of developing other infections
