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biology 2 > homeostasis and response > Flashcards

homeostasis and response Flashcards

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1
Q

what is homeostasis?

A

Homeostais is the regulation of internal conditions in a cell or organism to maintain optimum conditions for function in response to internal and external changes.

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2
Q

what does homeostasis control?

3

A
  • blood glucose concentration
  • body temperature
  • water levels
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3
Q

what do the automatic control systems include?

and what do they do?

A
  • receptor- they detect stimuli
  • coordination centres- process info given from receptors (spinal cord, brain, pancreas)
  • effectors- bring about responses that restore optimum levels (muscles/glands)
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4
Q

what does the nervous system do?
and what does it consist of?

A
  • allows reactions to environments and co-ordinates behaviour
    -Central Nervous System (brain & spinal cord)
    -Peripheral Nervous System (all nerves)
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5
Q

Structure of neurones

A
  • axons- carry impulses
  • myelin sheath- insulates axons to prevent short circuits
  • dendrites- branches off cell body and recieve impulses
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6
Q

pathway through nervous system

A

stimulus -> receptor -> co-ordination centre -> effector -> response

sensory neurone AND motor neurone NOT RELAY

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7
Q

reflex arc

A

stimulus -> receptor -> sensory neurone -> CNS -> realy neurone -> motor neurone -> effector -> response

DOESNT pass through CONSCIOUS part of brain
automatic

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8
Q

sensory vs relay vs motor neurones

A

Sensory- long, cell body in middle
Relay- short, NO myelin sheath
Motor- long, lots of dendrites

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9
Q

what is a synapse and how do electrical impulses croos over?

A

A synapse is the gap between neurones

Chemicals called neurotransmitters diffuse acroos synapse carrying electrical impulse to receptor molecules.

drugs can bind to neurotransmitters

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10
Q

what is the cerebellum?
and where is it found?

A

responsible for muscle co-ordination and movement

bottom/back of brain

m for muscle and movement

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11
Q

what is the cerebRal cortex?
and where is it found?

A

responsible for consciousness, memory, intelligence and language

outer part of brain

2 c’s for consciousness

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12
Q

what is the medula?
and where is it found?

A

responsible for unconsious activity
i.e breathing and heart rate
brain stem infront of cerebellum

m for mindfullness - breathe in slowly reducing heart rate

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13
Q

why is so difficult for neuroscientits to study the brain?

A

is it incredibly complex and delicate

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14
Q

how can neuroscientists map regions of the brain?

A
  • studying patients with brain damage
  • electrically stimulating areas of brain- pushing electrode into brain
  • MRI scanning
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15
Q

what temperature do the enzymes in the body work best at?

A

37

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16
Q

where is the body temperature monitered and controlled?

A

thermoregulatory system in the hypothalamus

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17
Q

how is a change in temperature dected?

A

receptor cells in skin detect stimuli and sends impulses to receptors in thermoregulatory system

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18
Q

how does the body cool itself down?

A
  • vasodilation- blood vessels dilate, increasing blood flow to skin- increasing energy transfer
  • sweat- evapourates from skin, increasing energy transfer
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19
Q

how does the body warm itself up?

A
  • vasoconstriction- blood vessels constricts to reducing blood flow to skin
  • skeletal muscles contract rapidly- shivering- generate heat from respiration
  • hairs stand on end- creating insulating layer to trap warm air
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20
Q

what are the two main funcfions of the eye?

A

-accomadation- focusing on near or distant objects
-adaptation- dimming light

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21
Q

function of the retina?

A

has light receptor cells (rods and cones) to detect light intensity and colour of light, to send impulses to brain

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22
Q

difference between rods and cones?

A

cones arent as sensitive to light then rods

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23
Q

function of optic nerve

A

sensory neurone that carries impulse from eye to brain

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24
Q

function of sclera

A

white layer that covers eyeball to prevent damage

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25
function of cornea
**transparent** layer at **front** of eye that **refracts** light
26
function of iris
controls how much light enters pupil
27
function of ciliary muscles
relaxes and contracts to change shape of lens
28
function of suspensory ligaments
tightens and loosens to change shape of lens
29
function of lens
transparent disc that's shape is changed to **focus** **light** onto the **retina**
30
what is accomodation?
process of changing the shape of the lens to focus on near or distant objects
31
to focus on a near object...
- ciliary muscles CONTRACT - suspensory ligaments LOOSEN - lens THICKER- refracting light STRONGLY
32
to focus on a distant object
- ciliary muscles RELAX - suspensory ligaments TIGHTEN - lens pulled THIN- refracting light SLIGHTY | di**s**tant **s**lightly, dis**t**ant **t**ighten
33
myopia
short-sighteness
34
hyperopia
long-sightedness
35
where is the rays of light focused with myopia?
infront of retina- eyeball too enlongated
36
where is the rays of light focused with hyperopia?
behind retina- eyeball too short
37
concave lens
myopia caves inwards
38
convex lens
hyperopia looks like v
39
how to treat eye defects? | 4
- spectacle lenses - contact lens - laser eye surgery- adjusts thickness of cornea (myopia- reduce- less refraction,, vice versa hyperopia) - replacemnt lens- replaces lens with artificial- hyeropia- risks- cataracts, damage to retina
40
pituitary gland
- MASTER GLAND - secretes hormones to act on other glands to stimulate production of other hormones
41
pancreas what does if secrete what does it control
- secretes insulin - controls blood sugar levels
42
thyroid gland what does it secrete what does it control
- secretes thyroxine - controls metabolic rate, heart rate and temperature
43
adrenal gland
- secretes adrenaline - involved in 'fight or flight' response
44
ovaries
- secretes oestrogen - involved in menstrual cyle and development of female secondary sexual characteristics
45
testes
- secretes testerone - involved in production of sperm an development of male secondary sexual characteristics
46
what are hormones and where are they carried to?
chemical messengers carried in the blood to the target organ or tissue
47
if the blood glucose concentration levels are too high
- pancreas produces insulin - nsulin stimulates liver to convert excess glucose into glycogen & muscle cells to use glucose for respiration
48
if blood glucose levels are too low
- pancreas produces glucagon - binds to liver cells to break gycogen down into glucose released into blood
49
diabetes type 1
pancreas cannot produce enough insulin uncontrolled blood glucose levels glucose excreted with urine- thirsty treated with insulin injections
50
diabetes type 2
body cells can no longer respond to insulin obesity- risk factor treatment- reducing carbs, loosing weight, excersise
51
too much water in the blood | cell & adh
cells swell and burst less adh- less water reabsorbed
52
too little water in the blood | cells & adh
cells shrink more adh- more water reabsorbed
53
how does water leave the body? | 2
- sweat - exhalation from lungs
54
what else leaves sweat
- ions - water - urea
55
deanimation
excess amino acids from digestion of protien broken down in liver into ammonia
56
what is urea
ammonia is toxic and so conveted into urea
57
what is the hormone ADH and what does it do?
- anti diuretic hormone - CONSTANTLY released from pituitary gland - controls how much water reabsorbes into kidney tubules
58
filtration of blood in kidneys
- high pressure causes moevules small enough to move through pores of bloodstream
59
what is selective reabsorbtion? and what does it absorb?
- kidneys reabsorbing substances body needs - ALL glucose - enough water for constant levels - enough ioons for constant levels - NO urea
60
process of kidney dialysis
unfiltred blood from arm into dialysis machine and returned
61
dialysis fluid & blood
seperated by partially permeable membrane and goes opposing ways to allow exchange where concenteration gradient exists fluid: - glucose similiar to healthy blood - ions similiar to healthy blood - no urea
62
disadvantages of dialysis
- possibility of blood clots forming - many hours a week - strict diet - expensive
63
disadvantes of kidney transplant
- chance of rejection - immunosuppresent drugs^ supresses immune system - ^ vulnerable to other disease
64
FSH & LH
- follicle stimulating hormone - luteinising hormone
65
FSH
- FSH released by **pituitary** gland to stimulate production of **follicle** - egg matures in follicle and follicle produces **oestrogen** break down of lining- period | FSH **matures** egg and stimulates production of **oestrogen**
66
oestrogen
- oestrogen causes **growth** and **repair** of lining - **inhibits** production of FSH - when high enough- **stimulates** release of **LH** from pituitary gland
67
LH
- results in **ovulation**
68
progesterone
- **follicle** produces progesterone - **maintains** uterus lining - if egg **not** fertilised- progesterone levels **drop**- period
69
chemical contraceptives
- oral contraceptives - injection/implant/skin patch - Inrauterine devices- IUD
70
what do oral contraceptives involve
inhibits FSH production so no eggs mature two types - combined- oestrogen^ & progesterone (thick mucuc preventing sperm) - progesterone- fewer side effects
71
patch/implant/injection/IUD
- progesterone- thickens mucus of cervix- stops sperm swimming patch- one week implant- 3 years injection- 2 to 3 months IUD- insterted into uterus
72
barrier contraceptives
- condoms- prevent spread of STI - -diaphragms - spermicidal agents- kills sperm
73
natural contraceptive
abstaining from intercourse when in ovulation
74
surgical contraceptives
male and female sterilisation female- oviduvts cut and tied male- soerm ducts cut and tied- vasectomy
75
what hormones are used for infertility?
FSH & LH to stimulate egg production expensive
76
how does IVF treatment work? | in vitro fertilisation
- mother- FSH & LH - stimulates maturation of eggs - eggs collected and fertilised with father's sperm in lab - develop into embryos - 1 or 2 place into mother's womb
77
risks of IVF
- low success rate - several- possible multiple births - people against- more embryos produced than used
78
adrenaline production
- procued by adrenal glands in times of fear or stress - increase heart rate and delivery of oxygen and glucose to brain and muscles- preparing for fight or flight - pupild dilate- more light- see clearly
79
thyroxine production
- produced in thryoid to regulate metabolic rate - growth and develoment - produced by TSH- pituitary - stimulates BMR (Basal Metablic Rate) & protein synthesis
80
thyroxine negative feedback
too high- inhibit TSH too low- TSH
81
what is negative feedback?
when the body responds to increase or decrease in a factor by returning it back to original level
82
roots tropisms
NEGATIVE phototropism POSITIVE gravititropism
83
shoots tropisms
POSITIVE phototropism NEGATIVE gravitropism
84
3 plants hormones
- auxins - gibberellin - ethene
85
auxins in shoots
- goes to shaded side- stimulates growth in cells- shoot bends towards light - more light= more photosynthesis - bends not straight usually evenly distributed at tip IF horizontal- moves to lower side- more growth- upwards bc + gravitropism
86
auxins in roots
IF horizontal- moves lower side- less growth- downwards bc - gravitropism
87
gibberellins
- important in initiating seed germination- when seeds starts to grow - flowering & growth of fruit
88
ethene
- gas involved in cell division and ripening of fruits
89
how are auxins used
- selective **weed** **killers**- causes cells to grow too rapidly- death- broad leavves weeds - **rooting** **powder**- plants w desriable featues cloned by taking cutting and using rooting powder to increase growth - **promote** **growth** in **tissue** **culture**- ^ another way of cloning- cells from plant into growth medium w nutrients- auxins added
90
how is ethene used
food industry - fruit picked unripe as firm so less bruised fom transport- exposed to ethene to stimulate enzymes involved in ripening- more suitable to be sold
91
how is gibberellins used
- ending seed dormancy- when seed unavble to germinate - promote flowering- quicker - increasing fruit size- seedless fruit sprayed- seeds produce g

biology 2 (3 decks)

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