B3 Flashcards

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1
Q

What are sensory neurones?

A
  • neurones that carry electrical impulses from the receptor cells to the CNS
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2
Q

What is the nervous system?

A

The nervous system consists of the brain and spinal cord which form the CNS and also several other neurones which respond to changes in the external environent

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3
Q

What are relay neurones

A
  • neurones that carry the electrical impulses from sensory to motor neurones (in the CNS)
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4
Q

What are motor neurones?

A
  • neurones that carry impulses from the CNS to the effectors
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5
Q

What are receptors?

A
  • groups of cells that detect a stimulus
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6
Q

What are effectors?

A
  • muscles or glands
  • will either contract or release a hormone
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7
Q

What is the CNS

A
  • the CNS is made up of the brain and spinal cord
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8
Q

What is a reflex action?

A
  • an automatic/ involuntary action
  • occur without thinking
  • impulse will not go to brain
  • e.g: Stimulus -> Receptor Cells -> Sensory Neurone -> Spinal Cord -> Motor Neurone -> Effector -> Response
  • much faster by not using brain
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9
Q

Reflexes Practical?

A
  • ruler drop time
  • can be affected by levels of caffeine, mass of ruler, which hand
  • use v2 - u2 = 2 to work out time
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10
Q

What does the cerebellum do?

A
  • co-ordinates muscular activity + balance
  • controls involuntary movements
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11
Q

What does the cerebal cortex manage?

A
  • memories
  • personality and complex emotions
  • learning and conscious thought
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12
Q

What does the medulla do?

A
  • controls essential automatic actions
  • such as breathing and heart rate
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13
Q

What does the hypothalmus do?

A
  • regulates temperature
  • regulated water balance
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14
Q

What does the pituary gland do?

A
  • known as the master gland
  • stores and releases many hormones
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15
Q

How can you scan the brain?

A
  • CT/ X-RAY scans (risk of radiation exposure)
  • MRI (less risk of any radiation)
  • Damage to the brain can be used to find brain functions
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16
Q

What is the sclera?

A
  • tough white layer of the eye that protects it from damage
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17
Q

What is the cornea?

A
  • transparent front part of the sclera that refracts light into the pupil
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18
Q

What is the pupil?

A
  • The hole in the center of the eye through which light passes through
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19
Q

What is the iris?

A
  • rings of muscles that control the size of the pupil
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20
Q

What is the retina?

A

-an area of light receptive cells at the back of the eye

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21
Q

What are receptor cells for colour in the eye?

A
  • cone cells
  • 3 types for red green and blue
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22
Q

What is the optic nerve?

A
  • nerve which sends signals to the brain from the eye
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23
Q

What are rod cells?

A
  • receptor cells which are sensitive to dim and bright light
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24
Q

What happens when there is low levels of light?

A
  • Radial muscles contract
  • Circular muscles relax
  • more light is let in as pupil dilates
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25
Q

What happens when there is high levels of light?

A
  • radial muscles relax
  • circular muscles contract
  • less light is let in as pupil constricts
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26
Q

What happens to the lens for far objects?

A
  • suspensory ligaments contract
  • cilliary muscles relax
  • lens becomes flatter and there is less refraction of light
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27
Q

What happens to the lense for near objects?

A
  • suspensory ligaments relax
  • cilliary muscles contract
  • lens becomes more thick and contracts and there is more light refraction
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28
Q

What is myopia?

A
  • the lens is too curved/ the eyeball is too long
  • this means the light refracts before the retina
  • light is refracted too much
  • can be fixed using concave lens
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29
Q

What is hyperopia?

A
  • lens is too thin or eyeball is short
  • light refracts too far on the retina
  • light is not refracted enough
  • can be fixed using convex lens
30
Q

Differences between endocrine system and the nervous system

A
  • hormones are chemical messengers (nervous system is electrical)
  • Hormones are slow acting
  • Hormones are long lasting
  • Hormone travel in the blood
  • Hormones are secreted in glands
31
Q

What is the endocrine system?

A
  • name given to all the endocrine glands and the hormones they produce
32
Q

Thermoregulation

A

The body needs to be maintained at about 37 degrees fro optimum enzyme activity

33
Q

Homeostasis?

A

The maintaining of internal body conditions even when external and internal environments change

34
Q

Thermoregulation cycle?

A

Receptors (blood vessels, skin) notice temp change -> Thermoregulation centre in Hypothalamus -> response from effectors

35
Q

What happens when the body is cold?

A
  • Contract Erector muscles to raise hairs (creates small layer of insulating hair
  • Blood Vessels will constrict (vasoconstriction) to increase distance from skin so less heat is lost to the environment via the skin
  • We do more cellular respiration in the muscles so we shiver and contract more giving off thermal energy as a waste product
36
Q

What happens when the body is too warm ?

A
  • Erector muscles relax, hairs go down, no layer of insulating air
  • Blood vessels will dilate (vasodilation) to decrease distance from skin so more heat is lost to environment via skin
  • sweat is produced (water+salt) and because it evaporates heat is taken with it, as it taken energy/heat energy to evaporate the sweat
37
Q

What happens after we eat

A

Glucose levels in the blood increase (constant high blood sugar) is bad for you

38
Q

How do we combat increased blood glucose levels

A
  • Pancreas detects this change and releases the hormone INSULIN which reduces blood glucose levels by stimulating an enzyme reaction to turn excess glucose into GLYCOGEN in the liver
  • glucose goes from blood to cells
39
Q

How do we combat decreased blood glucose levels

A
  • Pancreas detects the change and releases hormone GLUCAGON which stimulates the reaction to turn glycogen into glucose in the liver cells
  • This is then used for respiration
  • glucose goes from cells to blood
40
Q

what is Diabetes?

A

a disease where the body cannot regulate blood glucose levels

41
Q

Difference between Type 1 and Type 2 Diabetes?

A

Type 1 is a lifelong condition you are born with where the body immune system attacks the cells that make insulin
Type 2 is a condition that comes later in life when the body becomes resistant to insulin

42
Q

How treat Type 1 Diabetes?

A

Insulin Injections, good diet and exercise

43
Q

How to treat Type 2 Diabetes?

A

Low Sugar diet with regular effect NO EFFECT WITH INSULIN INJECTIONS

44
Q

Regulating Water levels?

A

water levels are regulated in the kidney and in the brain

45
Q

Lack of water in the blood?

A
  • Decreased water concentration detected in the hypothalamus
  • more ADH released (pituitary gland)
  • more reabsorbed in the blood from the nephrons
46
Q

Too much water on the blood?

A
  • increased water concentration detected in the hypothalamus
  • less ADH released (from the pituitary gland)
  • less water reabsorbed into the blood
47
Q

Thyroid gland?

A
  • In the neck
  • releases hormone thyroxine
  • this controls metabolism
48
Q

Adrenal Gland?

A
  • on top of kidneys
  • releases adrenaline
  • prepares flight or fight response
49
Q

Pancreas

A
  • secretes insulin
  • controls blood sugar
50
Q

Pituary Gland?

A
  • stimulates stimulation of other hormones in different glands
51
Q

What does FSH do ?

A
  • stimulates the release of oestrogen
  • matures the egg cell
  • Peaks at day 0 and lowest at day 14-21
  • produced in the pituary gland
52
Q

What does Oestrogen do?

A
  • inhibits the release of FSH
  • stimulates the release of LH
  • causes the uterus lining to thicken
  • secreted in the ovaries
  • day 7-21 peak
53
Q

What does LH do?

A
  • secreted in the pituary gland
  • stimulates ovulation
  • day 14 peak
54
Q

What does progesterone do?

A
  • if pregnant inhibits LH and FSH and levels of P will be high
  • if pregnant will maintain uterus lining
  • if pregnant allows mucus to form a lining at the cervix
  • secreted from the empty egg follicle
  • If no fertilisation takes place from day 28, the uterus lining and egg will be pass out the vagina AS PROGESTRONE WILL cease to release
  • cycle restarts
55
Q

Forms of contraception?

A
  • combined pill - oestrogen + progesterone (inhibits FSH and LH, egg inhibited) has to be taken everyday, bad side effects such as increased BP
  • pill only - progesterone (mucus layer, plus inhibition), less side effects
  • spermicides, chemicals that destroy sperms
  • condoms, stop STD’s and sperm, no side effects
  • IUD, lasts 2-5 years can contain progesterone
  • Abstinence - avoiding sex, religion
  • surgery - permanent sterilisation
56
Q

Fertility Drugs?

A
  • for females who may not be able to ovulate
  • contains FSH and LH to mature drugs and to ovulate
57
Q

Blocked Oviduct Fertility Issue?

A
  • Fertility drugs are given to mature and release eggs
  • eggs are taken and mixed with sperm outside the body
  • fertilised eggs/uterus are then syrigned into uterus (IVF)
  • solves fertility
  • expensive
  • embryos can be stored
  • limited success rate
  • unused embryos can be donated
  • mentally and physically draining
  • IVF can lead to multiple births
58
Q

What is negative feedback?

A
  • a homeostatic mechanism where the body detects a change and makes an adjustment to return to normal
59
Q

Thyroxine Feedback loop?

A
  • If thyroxine levels in the body increase the brain will detect this
  • It will send a signal to a motor neurone to a gland (effector), the pituary gland
  • The pituary gland will release less TSH (thyroxine stimulating hormoe) which will stimulate less thyroxine to be produced
  • This can be done vice versa for too little thryoxine
60
Q

Effect of Adrenaline?

A
  • pupils dilate to let more light in
  • heart rate increases (to pump blood faster)
  • glycogen reserves in muscle cells break down (to release more glucose for more respiration)
  • Blood from the digestive system is redirected to skeletal muscles
  • breathing rate increases to get more oxygen in
61
Q

Why could there (diet related) not be enough thyroxine?

A
  • lack of iodine, used to make thyroxine
62
Q

What is the effect of less thyroxine?

A
  • lower metabolism
  • lower levels of protein synthesis
  • vice versa
63
Q

What happens if water potential in blood is too high (red blood cells)

A
  • red blood cells with lyse(burst)
64
Q

What happens if water potential in blood is too low (red blood cells)

A

red blood cells will shrink and shrivel

65
Q

Process of Excretion?

A
  • each kidney is supplied with oxygenated blood via the aorta/renal artery
  • kidney cleans the blood, removing excess water, urea and salts
  • the cleaned blood is sent back to the heart via the renal vein/vena cava
  • the waste is sent to the bladder (urine)
66
Q

What is phototropism?

A

growth in response to light

67
Q

What is gravitropism?

A

growth in response to gravity

68
Q

What do Auxins do?

A
  • in roots they slow down/inhibit growth
  • in shoots they stimulate growth
  • auxins will move towards the darker side of the shoot to bend it towards the light
69
Q

Uses of Auxins?

A
  • selective weedkiller for broad leave plants, will grow too fast and die
  • used for rooting powder
70
Q

Uses of Giberellins?

A
  • help with seed germination
  • can induce flowerings
  • growing larger seedless fruits
71
Q

Use of ethene?

A
  • induces ripening
  • ethene inhibitors can delay ripening