Homeostatis And Response Flashcards
(120 cards)
1
Q
What is the function of the iris?
A
Controls size of pupil and amount of light reaching retina
2
Q
What is the function of the ciliary muscles and suspensory ligaments?
A
Can change the shape of the lens to focus on near or distant objects
3
Q
What is accommodation?
A
Process of changing the shape of the lens to focus on near or distant objects
4
Q
To focus on near objects?
A
^Ciliary muscles contracting
^Suspensory ligaments loosen
^Lens becomes thicker
^Lens strongly refracts light rays
5
Q
What does the eye do to focus on distant objects?
A
👁 Ciliary muscles relax
👁Suspensory ligaments are pulled tight
👁Lens is pulled thin
👁Lens slightly refracts light rays
6
Q
What are the 2 common defects of the eye?
A
👁Myopia - short sightedness
👁Hyperopia - long sightedness
7
Q
What does it mean if your eye has a common defect?
A
When rays of light do not focus on the retina
8
Q
How can myopia and hyperopia treated?
A
With spectacle lenses that refract the light rays so they can focus on the retina
9
Q
Why does our pupil become smaller when exposed to bright light?
A
To protect the retina from damage
10
Q
Name some new eye treatment technologies?
A
*Contact lenses
*Laser eye surgery (changes cornea shape)
*Eye lens replacement
11
Q
What is the endocrine system?
A
Made up of glands which secrete hormones directly into the bloodstream
12
Q
What are hormones?
A
Chemical messengers carried in the blood
13
Q
What do hormones do?
A
Hormones target organs where they produce an effect
14
Q
What is the difference between the effects of hormones and the nervous system?
A
Compared to the effects of the nervous system, hormones are slower and act for longer
15
Q
What is the pituitary gland?
A
It’s the master gland
16
Q
Where is the pituitary gland found?
A
In the brain
17
Q
What is the function of the master gland?
A
Secrete hormones in response to body conditions, some of the hormones act on other glands to stimulate other hormones to be released to bring about effects
18
Q
What does adrenaline do?
A
●Produced by adrenal glands in times of fear or stress
●Increases heart rate which increases the delivery of oxygen and glucose to the brain and muscles
●Preps body for fight or flight
19
Q
Where is thyroxine produced?
A
In the thyroid gland
20
Q
What is the function of thyroxine?
A
£Increases metabolic rate
£Controls growth and development in young animals
21
Q
How is the release of thyroxine controlled?
A
By negative feedback
22
Q
Why might the endocrine glands be called ductless glands?
A
Enzymes from glands (like the salivary gland) pass into tubes called ducts, the endocrine system can be called ductless because the hormones pass into the blood
23
Q
Where is blood glucose concentration monitored and controlled?
A
The pancreas monitors and controls the blood glucose concentration
24
Q
What happens when blood concentration is too high?
A
Pancreas releases more insulin (hormone)
#Insulin causes glucose to move from the body into cells like fat and muscle cells so they can use glucose for energy
#Liver and muscle cells convert excess glucose into glycogen for storage
25
What happens when blood glucose concentration is too low?
26
Describe type 1 diabetes?
*Caused by pancreas failing to produce enough insulin
*Results in uncontrolled high blood glucose levels
*Usually treated with insulin injections
27
What is negative feedback?
Action taken by the body to return something in the body back to normal/optimum level when that something wasn't at the right level
28
State the 3 ways water leaves the body?
Water leaves the body from the lungs during breathing, skin when sweating and urine
29
When concentration of blood changes, what happens to the body cells?
If concentration of blood changes, body cells will LOSE OR GAIN TOO MUCH WATER BY OSMOSIS (high concentration to low concentration )
30
Where is the balance of water and ions in the body regulated?
In thr KIDNEYS AND THEY ALSO EXCRETE UREA
31
What is urea?
A WASTE PRODUCT PRODUCED BY THE LIVER FROM THE BREAKDOWN OF PROTEINS and contains nitrogen
32
What does the digestion of proteins result in?
The digestion of proteins from food results in EXCESS AMINO ACIDS
33
What happens to the excess amino acids produced from the digestion of proteins from food?
CONVERTED INTO AMMONIA IN A PROCESS CALLED DEAMINATION
34
What is deamination?
BREAKDOWN OF EXCESS AMINO ACIDS
35
Is ammonia toxic?
YES
36
Ammonia is toxic, so what happens to it in the body?
IMMEDIATELY CONVERTED TO UREA AND SWNT TO THE KIDNEYS FOR SAFE EXCRETION
37
What is the control of the water level in the body an example of?
NEGATIVE FEEDBACK
38
The three steps the kidneys produce urine?
1) Filter the blood
2) Selective reabsorption of useful substances such as glucose, some ions and water
3) Leaves urea and excess water and ions to form urine
39
Where does the process of the kidneys producing urine take place?
These processes take place in MILLIONS OF SMALL TUBES IN THE KIDNEYS CALLED TUBULES
40
What is selective reabsorption?
Process of active transport (low to high) that reabsorbs useful molecules back into the blood from kidney tubules
41
What hormone controls water level?
The water level in the body is controlled by the hormone ADH
42
How does the hormone ADH work?
*ADH IS RELEASED BY THE PITUITARY GLAND WHEN THE BLOOD IS TOO CONCENTRATED (high concentration of red blood cells)
*IT PASSES, IN THE BLOOD, TO THE KIDNEY TUBULES WHERE IT CAUSES MORE WATER TO BE REABSORBED BACK INTO THE BLOOD
43
How are people who suffer from kidney failure treated?
BY ORGAN TRANSPLANT OR BY USING KIDNEY DIALYSIS
44
How does dialysis work?
TAKES OVER THE ROLE OF KIDNEYS , USED TO REMOVE WASTE PRODUCTS FROM THE BLOOD, THREE TIMES A WEEK
45
What play many roles in human reproduction?
Hormones
46
What do sex hormones cause to happen during puberty?
During puberty, sex hormones cause SECONDARY SEXUAL CHARACTERISTICS TO DEVELOP (OESTROGEN+TESTOSTERONE)
47
What is the main female sex hormone?
Oestrogen
48
Where is oestrogen from?
Ovaries
49
What happens for females when they hit puberty?
Eggs begin to mature and be released = ovulation
50
What is the main male sex hormone?
Testosterone
51
Where is testosterone produced and what does it do?
●Produced by testes
●Stimulates sperm production
52
What is the difference between the production of sex hormones in men and women?
After puberty, MEN PRODUCE SPERM CONTINOUSLY, WOMEN HAVE A MONTHLY CYCLE OF EVENTS (menstrual cycle)
53
How many hormones are involved in a woman's menstrual cycle?
Four hormones
54
Name the four hormones involved in a woman's menstrual cycle?
♡Follicle stimulating hormone(FSH)
♡Oestrogen
♡Lutenising hormone (LH)
♡Progesterone
55
Where is the follicle stimulating hormone (FSH) secreted during the menstrual cycle?
By the pituitary gland
56
What does the follicle stimulating hormone cause during the menstrual cycle?
■Causes egg to mature in ovaries in the first part of thr cycle
■Stimulates ovaries to produce oestrogen
57
Where is oestrogen secreted during the menstrual cycle?
By ovaries
58
What does the oestrogen hormone cause during the menstrual cycle?
♡Inhibts (prevents) FSH release
♡Stimulates LH release
♡Makes uterus lining grow again after menstruation
59
Where is the lutenising hormone secreted by during the menstrual cycle?
●Secreted by pituitary gland
60
What does the liutenising hormone do during the menstrual cycle?
Stimulates release of egg from the ovary (ovulation)
61
Where is progesterone secreted by during the menstrual cycle?
Secreted by an empty follicle (egg sac) in the ovaries
62
What is the function of progesterone during the menstrual cycle?.
♡Maintains lining of uterus during the second half of the cycle
♡Inhibts (prevents) FSH release and LH release
63
What is a follicle in a woman?
An egg sac
64
What do contraception and fertility treatments raise concerns of ?
Ethical issues
65
Can plants respond to changes in their external environment?
Yes
66
How do plants respond to changes in their external environment?
🌻Roots and shoots growing towards or away from a particular stimulus (anything that triggers a change)
🌻Plants flowering at a particular time
🌻Ripening of fruits
67
Are plants responses to changes faster or slower than animal responses?
Slower than animal responses
68
What is it called when a plant responds by growing in a particular direction?
Tropism
69
What is tropism?
When a plant responds by growing in a particular direction
70
How many types of tropism are there?
2, Gravitropic and Phototropic
71
Describe gravitropic in terms of the shoots?
🌸Growth of the shoots is negatively gravitropic (geotropic)🌸Stem grows against force of gravity = upwards
72
Describe gravitropism is terms of the roots?
🌸Growth of roots is positively geotropic as the roots grow in the direction of gravity = downwards
73
What is gravitropic?
When the stimulus (change) is gravity. For example the plant is placed on its side. Shoots are negative and roots are positive geotropic
74
What is phototropism?
The stimulus (change) is light
75
Describe phototropism in terms of the plant shoots?
Plant shoots grows towards the light = positively phototropic
76
Describe phototropism in terms of the roots?
Roots grow away from the light = negatively phototropic
77
What are auxins?
A plant hormone which controls tropisms
78
What plant hormone controls tropisims?
Auxins
79
What happens to auxin in response to light?
1) Auxin diffuses down the shoots stimulating growth
2) One side of the shoot is in the light so auxin diffuses away into the shade
3) Shoot in the shade has more auxin so grows faster causing the shoot to be more elongated and bends towards the light
80
Describe how the roots change in a response to gravity?
Auxin moves to the bottom of the root, causes less elongation so root grows downwards, growth inhibited (reduced)
81
Define homeostasis?
The regulation of the internal conditions of a cell or organism in response to internal or external changes
82
Why is homeostasis important?
Important as it keeps conditions constant for enzyme action and cell functions
83
What is thr function of the cerebellum?
Coordinates movement and balance
84
What does the medulla control?
Controls automatic/conscious actions like heart bear and breathing
85
What is the function of the optic nerve?
Carries impulses from the retina to the brain
86
What is the sclera?
Forms a tough outer layer, transparent region at the front called the cornea
87
What organ is the eye?
A sense organ
88
What does the retina contain?
Contains receptors cells that are sensitive to brightness and light
89
What is negative feedback?
An important type of control, responds when conditions change from ideal so returns conditions back to ideal, continuous cycle
90
What temperature should the human body be?
Around 37.c
91
Why should the body be at 37.c ?
Its an optimum temperature for enzymes to work
92
What sort of behaviour does the brain control?
Complex behaviour
93
What is the brain made from?
Billions of inter connected neurones and has different regions thar carry out different functions
94
What happens when the body temperature gets too high?
●Blood vessels widen, directing more blood to the surface of skin ( Vasolidation)
●More sweat produced from sweat glands and evaporates
95
What is the function of the thermoregulatory centre?
●monitors and controls body temp
96
How does the thermoregulatory center know when to act?
●Receptors that monitor the temp of blood flowing through the brain
●Recieves info (impulses) from temperature receptors in skin
97
Where is the thermoregulatory center located?
In the brain
98
Why are thr temperature receptors in the skin useful?
Give thr brain an early warning of changes in external temperature, allows temperature to be adjusted to stop body temperature changing, like putting on more clothes
99
Blood vessels in the skin can't move so what happens to change energy transferred to surroundings?
They narrow or widen to adjust how much energy is transferred to the outside
100
Homeostasis includes the control of ...?
●Blood glucose
●Body temperature
●Water and ion levels (like potassium and calcium)
101
What control systems does homeostasis control?
●Responses using nerves
●Chemical responses using hormones
102
What are the 3 stages og negative feedback?
1) receptors detects a change in stimulus
2) the coordinating centre compares the stimulus to a set point
3) an effector produces a response to correct any difference from the set point
103
What are control systems?
Cells called receptors detect stimulus (change in environment)
104
What do coordinating centres do and name some?
Recieve and process info from receptors. Brain, spinal cord, pancreas
105
What are efffectors and give an example?
They are muscles or glands which bring about responses that restore optimum levels
106
What is the cerebal cortex responsiblefor?
Responsible for consciousness, intelligence, memory and language
107
How are neuroscientists able to map out the brain regions to particular functions?
●Studying patients with brain damage
●Electrically stimulate different parts of the brain
●MRI scanning techniques
108
Why is investigating the brain difficult?
Because of its complexity and delicacy
109
What are the 5 step of the reflex actions?
1) pain stimulus detected by receptors
2) impulses from receptors pass along the sensory neurone to the CNS
3) impulse passes through a relay neurone
4) motor nuerone carries an impulse to the effector
5) effector (usually muscle) responds ie by removing hands from source of pain
111
Do reflex actions involve the brain?
No, don't involve the conscious part of thd brain
112
How do neurones communicate?
Communicate via synapses
113
What are the three main brain regions?
☆Cerebal cortex
☆Cerebellum
☆Medulla
114
What is the function of the nervous system?
Allows humans to react to their surroundings and coordinate their behaviour
115
What is thr CNS?
The centeral nervous system
116
Where is the CNS located?
Brain and spinal cord
117
What is the function of thr CNS?
Coordinates the response of the effectors. For example muscles contracting or sweat glands secreting hormones
118
What happens if body temp is too low?
● blood vessels narrow directing blood away from surface of skin (vasconstriction)
●Sweating stops
●Skeletal muscles contracting and relax quickly shiver (which transfers more heat to the blood)
119
What happens when skeletal muscles contracting and relax quickly when body temp is too low?
shiver which transfers more heat to the blood)
120
Where does deamination happen?
In the LIVER
121
What are reflex actions?
Automatic and rapid so they can protect the body from danger
