B5 Homeostasis and Response Flashcards
1
Q
Define Homeostasis
A
An organisms ability to regulate/control its internal conditions so crucial reactions can happen at optimal rates
2
Q
What does homeostasis regulate?
(3 things)
A
-blood glucose concentration
-Internal Temperature
-Water levels
3
Q
What does CNS stand for?
A
Central nervous system
4
Q
What makes up the CNS?
A
Brain + Spinal cord
5
Q
What does PNS stand for?
A
Peripheral Nervous system
(All other nerves in the body)
6
Q
What is the order that an impulse travels to the CNS?
A
Stimulus➡️Receptor➡️Sensory Neurone➡️Relay neurone➡️Motor neurone➡️Effector
7
Q
What is a reflex arc?
A
Signal bypasses brain - it is an unconscious response to a stimulus
8
Q
What is a synapse?
A
Gap between neurones
9
Q
How does the signal pass over a synapse?
A
Over chemicals (neurotransmitters)
10
Q
The two types of effector
A
Muscles + Glands
11
Q
Function of glands?
A
Secrete chemicals (hormones)
12
Q
What is the RPA for reaction time
A
Ruler drop test
13
Q
How do you perform the ruler drop test?
A
- Drop ruler from above between finger and thumb
-Measure the distance fallen before it is caught
-Repeat and calculate a mean
14
Q
Independent variable of ruler drop test
A
Stimulant ( eg energy drink) increases neurotransmission
Depressant (alcohol) decreases neurotransmission
15
Q
Where is the cerebral cortex located
A
Front top of the brain
16
Q
Where is the cerebellum
A
Back bottom of the brain
17
Q
Where is the medulla
A
Very bottom of the brain (tube ish thing in the middle)
18
Q
Function of cerebral cortex
A
-memory
- Speech
-Problem solving
19
Q
Functions of cerebellum
A
Motor skills:
-movement
-balance
-coordination
20
Q
Function of medulla
A
Unconscious actions:
-Heart and breathing rate
-signals to adrenal gland to release adrenaline
21
Q
MRI SCANS…
A
Allow doctors to see the brain activity without surgery
22
Q
Function of cornea (eye)
A
Refracts light rays
23
Q
Function of the iris (eye)
A
Regulates amount of light entering the pupil
24
Q
Function of pupil (eye)
A
A hole that allows light to enter the eye
25
Function of lens (eye)
Focuses light on retina
26
Function of ciliary muscle (eye)
Involved in changing shape of lense
27
Function of suspensory ligament (eye)
Holds lens in place and is involved in changing shape of lens
28
Function of retina (eye)
Contains light receptors at the back of the eye
29
Function of the optic nerve(eye)
Sends impulses to brain
30
When trying to see an object FAR in the distance, the ciliary muscles ______, the suspensory ligaments ______ and the lens gets ______
When trying to see an object far in the distance, the ciliary muscles RELAX, the suspensory ligaments TIGHTEN and the lens gets THINNER
31
When viewing a near object the ciliary muscles ___ , the suspensory ligaments ___ and the lens gets ____
Ciliary muscles CONTRACT, the suspensory ligaments LOOSEN, the lens gets THICKER
32
What is MYOPIA
Short sightedness
33
What is HYPEROPIA
Long sightedness
34
How can we treat hyperopia and myopia
Glasses
laser surgery
35
What is thermoregulation
a homeostatic process that maintains a steady internal body temperature despite changes in external conditions.
36
How does the body cool us down when we are hot?
Sweat glands produce water which evaporates off of the skin, taking away the heat.
Blood vessels vasodilate so they are closer to the skin
37
How does the body attempt to heat us up when we are cold?
Body hairs stand on end to trap air, a layer of insulation.
Shivering - muscles contract and relax rapidly, so produce more heat through respiration
Blood vessels vasoconstrict, get further away from skin
38
What is the endocrine system?
A system of glands that secrete hormones to send signals to effectors, transported by blood
39
What part of the brain is responsible for thermoregulation
The hypothalamus
40
What does the thyroid secrete and control
Thyroxine, controls growth and metabolism
41
What is the master gland?
Pituitary gland
42
What does the pituitary gland do?
It sends signals to all other glands
43
Adrenal glands secrete…
Adrenaline
44
Pancreas secretes…and…, to control …
Insulin and glucagon, to control blood sugar
45
Ovaries release … and secrete…
Eggs and hormones
46
Testes produce…
Sperm
47
Which glands make up the endocrine system? ( 7 things)
Pituitary gland, Thyroid, Pancreas, Adrenal Glands, Ovaries, Testes
48
When you have high blood sugar levels your body reacts by…
- The pancreas secretes insulin
-This causes glucose to move from bloodstream into cells to be used for respiration
-Excess glucose is converted into glycogen as energy store
49
What disease is linked to high blood sugar levels?
Type I diabetes
- Pancreas cannot produce (enough) insulin
-Injections needed
50
When you have low blood sugar levels your body reacts by…
-Pancreas secretes glucagon
-Causes liver and muscles to convert glycogen back into glucose ( Example of negative feedback)
51
What disease is linked to low blood sugar levels?
Type II diabetes
-Cells do not absorb glucose as they should
-Obesity increases risk of developing
52
What is a negative feedback loop?
A negative feedback loop responds when conditions change from the ideal or set point and returns conditions to this set point.
53
Water is lost from the body through…
(3 things)
Exhalation, Sweat, Urination
54
Excess water is removed from the blood by… into the ….
KIDNEYS into the BLADDER
55
How is urine formed?
Excess water is mixed with urea
56
Where is urea created
Liver
57
Urea contains…
Ammonia (NH3) from amino acids from excess proteins broken down by the liver
58
Kidney also filters out… from urine
Glucose and useful minerals and ions for the body to use
59
What does ADH (anti diuretic hormone) do? Where is it ADH from?
It causes tubules in kidneys to reabsorb more water into blood stream. ADH is secreted by the Pituitary Gland
60
If water levels are too high, less … is made, so more water is….
Less ADH is made, so more water is sent to the BLADDER to leave the body as urine
61
If kidneys don’t work properly, …. Is needed
Dialysis
62
What is dialysis?
Blood is filtered by a dialogue machine.
If not done, ammonia/urea buildup will be poisonous
63
ADH and the kidneys are an example of
(N F)
Negative Feedback
64
FSH (Follicle Stimulating Hormone) is secreted by the
Pituitary Gland
65
FSH causes an … to …… and the ovaries to produce ….
Egg, Mature, Oestrogen
66
Oestrogen is produced by the
Ovaries
67
Oestrogen causes the uterus lining to
Thicken
68
Oestrogen inhibits … so no more eggs mature until the next cycle
FSH
69
Oestrogen causes the pituitary gland to secrete
LH (Luteinising Hormone)
70
LH causes
The egg to be released, which starts travelling to the uterus, via the oviduct
71
72
A sperm cell can fertilise the egg while in the
oviduct
73
Progesterone is secreted by the …. To maintain….
Ovaries , Uterus lining
74
Order of hormones in the MENSTRUAL CYCLE
FSH➡️OESTROGEN➡️LH➡️
PROGESTERONE
75
Types of contraception (6)
-FSH inhibiting pills, no eggs mature
-Progesterone injection/implant(convenient) to stop eggs being released
-Condom/Diaphragm: prevents sperm entering the vagina
-IUD(copper coil): stops egg inbedding in lining
-Avoiding sex for a time after egg released
-Clamping oviduct or vasectomy (cutting sperm tubes)
76
Fertility treatments…(2)
-FSH/LH injections- Simple!
-IVF (in-vitro fertilisation) - hard ,expensive
77
What is IVF
Eggs collected after inducing release with LH to be fertilised in a lab. Viable embryos inserted back into woman’s uterus
78
Disadvantages of IVF
-Very expensive
-Very low success rate
-Can potentially cause multiple embryos to develop
79
Disadvantages of dialysis
-Risk of infection
-Time consuming
-Very rigid diet
80
What does adrenaline cause?
Increases blood flow and breathing rate, prepares you for fight or flight
81
If there is not enough thyroxine, the hypothalamus releases … which causes,pituitary gland to release … which causes thyroid to release more…
TRH, TSH, THYROXINE
82
What is this an example of?
(TRH ➡️TSH➡️THYROXINE)
Negative feedback
83
What does thyroxine do
Controls metabolic rate
84
3 plant hormones
Auxin
Gibberellins
Ethene
85
Function of Gibberellins
-Induce germination
-Promote flowering
-Increase fruit size
86
Function of Ethene
-Causes ripening
87
Why do we store bananas separately
They release ethene gas, which causes ripening
88
Function of auxins
-Promotes growth of a plant shoot. It gathers on the shaded side, to grow/elongate more quickly, towards the sun
-Inhibits root growth. It gathers on the bottom of roots, so it grows downward.
89
90
What is tropism
Any response to a stimulus
91
What is positive tropism
Grows towards a stimulus
92
What is negative tropism
Grows away from a stimulus
93
What is geotropism
A response to gravity
94
What is photo tropism
A response to light
95
What is hydrotropism
A response to water
96
3 uses of auxins
-Weedkillers
-Routing Powders
-Promoting growth in tissue cultures
97
Describe the Geotropism practical
-place seeds on damp cotton wool in a Petri dish stood on its edge
-Rotate the Petri dish after a few days to observe geotropism in roots
98
