Topic 5 - Homeostasis and Response Flashcards
(100 cards)
1
Q
What is abstinence?
A
Deliberately refraining from having sexual intercourse.
2
Q
What is accommodation?
A
The process of changing the shape of the lens to focus on near or distant objects.
3
Q
What is Adrenaline?
A
A hormone that is produced by the adrenal glands in response to fear or stress which increases the heart rate and boosts the delivery of blood to the brain and muscle as a part of the ‘fight or flight’ response.
4
Q
What is an Antidiuretic Hormone (ADH)?
A
A hormone that increases the reabsorption of water in the kidney tubules.
5
Q
What are the Coordination centres?
A
Areas of the body like the brain, spinal cord and pancreas that receive and process information from receptors.
6
Q
What is Deamination?
A
A process occurring in the liver that removes the amino groups from an amino acid to produce ammonia.
7
Q
What is Dialysis?
A
A method of treating kidney failure or disease where the blood is artificially filtered to move waste and toxins.
8
Q
What are the Effectors?
A
Muscles or gland which bring about response which restore optimum levels.
9
Q
What is Auxin?
A
A type of plant hormone which controls cell division and the ripening of fruits.
10
Q
What is Follicle Stimulating Hormone (FSH)?
A
A female reproductive hormone that cause the maturation of an egg in the ovary.
11
Q
What is geotropism/ gravitropism?
A
A plant’s directional growth response to gravity.
12
Q
What is Gibberellins?
A
A type of plant hormone which initiates seed germination.
13
Q
What is a gland?
A
A group of cells that secrete chemicals called hormone directly into the bloodstream.
14
Q
What is Glucagon?
A
A hormone produced by the pancreas that causes glycogen to be converted into glucose and release into the blood.
15
Q
What is homeostasis?
A
The regulation of the internal conditions of a cell or organism to maintain
optimum conditions for function in response to internal and external changes.
16
Q
What is Hyperopia?
A
A defect of the eye where nearby objects appear out of focus.
17
Q
What In Vitro Fertilisation (IVF)?
A
Fertilising a woman’s egg using sperm outside of the body.
18
Q
What is the Luteinising Hormone (LH)?
A
A female reproductive hormone that stimulates the release of an egg.
19
Q
What is myopia?
A
A defect of the eye where distant objects appear out of focus.
20
Q
What is negative feedback cycle?
A
A regulatory mechanism that reverses a change.
21
Q
What is Oestrogen?
A
The main female reproductive hormone which causes the uterus
lining to grow and repair.
22
Q
What is Phototropism?
A
A plant’s directional growth response to light.
23
Q
What are the receptors?
A
Organs or cells that detect stimuli.
24
Q
What is a reflex action?
A
A rapid and automatic response to a stimulus.
25
What is Selective Reabsorption?
Reabsorbing certain useful molecules (like glucose,
some ions and water) back into the blood after they have been filtered out.
26
What is a stimuli?
Changes in the environment.
27
What is the target organ?
The organ which a hormone acts on to produce an effect.
28
What's Testosterone?
The main male reproductive hormone produced by the testes and it stimulates sperm production.
29
What if the brain?
An organ made of billions of interconnected neurones which controls complex
behaviour and has different regions that carry out different functions.
30
What is the Central Nervous System (CNS)?
The brain and spinal cord which coordinate the response of effectors.
31
What is the eye?
A sense organ containing receptors sensitive to light intensity and colour.
32
What is the Thermoregulatory Centre?
An area of the hypothalamus in the brain which contains blood temperature receptors and regulates body temperature.
33
What is thyroxine?
A hormone produced by the thyroid gland that increases the metabolic rate in the body.
34
What is Type 1 Diabetes?
A disorder in which the pancreas fails to produce sufficient insulin which is characterised by uncontrolled high blood glucose levels.
35
What is Type 2 Diabetes?
A disorder where the body cells no longer respond to insulin produced by the pancreas.
36
What is Vasoconstriction?
The constriction of blood vessels?
37
What is Vasodilation?
The dilation of the blood vessels.
38
Give examples of conditions maintained by homeostasis in the body?
- Blood Glucose Concentration
- Body Temperature
- Water Levels
39
What two types of responses are used in body control systems?
Nervous and Chemical.
40
What three components do all control systems have?
- Receptors
- Coordination Centres
- Effectors
41
How does a stimulus lead to a response being carried out by the body?
- Stimulus is converted into an electrical impulse by the receptors.
- The electrical impulse passes along sensory neurones to the central nervous system.
- The CNS coordinates an appropriate response and an electrical impulse is sent along motor neurones to the effector, which carries out the response.
42
What sequence of events describe how the nervous system works?
Stimulus - Receptor - Coordinator - Effector - Response
43
Describe how a reflex action occurs via a reflex arc?
- The stimulus is detected by a receptor.
- And electrical impulse passes along a sensory neurone to the spinal cord.
- At a synapse between a sensory neurone and a relay neurone, a chemical diffuses across the gap and stimulates a new impulse which passes along the relay neurone.
- The same process occurs at a synapse between a relay neurone and a motor neurone
- At the effector, and appropriate response is carried out.
44
What is the difference between a reflex pathway and a conscious pathway?
Within a reflex pathway, the coordination centre is a relay neurone found in the spinal cord/ unconscious parts of the brain. In a conscious pathway, the coordination centre is in the conscious part of the brain.
45
What is the function of the cerebral cortex?
Controls consciousness, intelligence, memory and language.
46
What is the function of the cerebellum?
Controls muscular coordination.
47
What is the function of the medulla?
Controls unconscious activities e.g. breathing and heart rate.
48
Why is the investigation and treatment of the brain difficult?
- The brain is a complex and delicate organ.
- The brain is easily damaged and destroyed.
- Certain membranes prevents drugs from reaching the brain.
- The exact function of each part of the brain is not known.
49
What methods are used by scientists to determine brain function?
- Studying patients with brain damage
- Electrical stimulation of the brain
- MRI scans
50
Describe the structure and function of the retina?
The retina is a light sensitive layer found at the back of the eye. Light stimulates the retinal cells, Resulting in impulse being sent to the brain.
51
Describe the structure and function of the optic nerve?
The optic nerve connects the eye and the brain. It carries impulses to the brain so that an image can be visualised.
52
Describe the structure and function of the sclera?
The sclera is the tough outer layer of the eye which protects it's internal structures.
53
Describe the structure and function of the cornea?
The cornea is the curbed transparent layer at the front of the eye. It lets light into the eye and allow light to be focused onto the retina.
54
Describe the structure and function of the iris?
The iris is a muscle which controls the size of the pupil by contracting or relaxing. This allows the eye to adjust to bright and dim lighting.
55
Describe the structure and function of the ciliary muscles and suspensory ligaments?
The ciliary muscles and suspensory ligaments hold the lens in place and control it's shape.
56
Describe how the iris alters the size of the pupil in both bright and dim light?
Bright light: circular muscles contract and radial muscles relax - make pupil smaller to avoid retinal damage.
Dim Light : Circular muscles relax and radial muscles contract - makes pupil larger so more light can enter the eye.
57
How does the eye focus on a nearby object?
- Ciliary muscles contract
- Suspensory ligaments loosen
- Lens becomes thicker and more curved so light rays are refracted strongly
58
How does the eye focus on a far away object?
- Ciliary muscles relax
- Suspensory ligaments tighten
- Lens become thinner so light rays are refracted weakly
59
How can myopia be treated?
Myopia can be treated using glasses with a concave lenses, which spreads out light ray so they can be focused on the retina.
60
How can hyperopia be treated?
Hyperopia can be treated using glasses with a convex lenses, which brings the light rays together so they can be focused on the retina.
61
Where is body temperature controlled in the body?
It is controlled by the thermoregulatory centre in the hypothalamus of the brain.
62
What physiological changes occur when the body temperature is too high?
- Vasodilation - Blood vessels near the surface if the skin dilate so more heat is radiated away.
- Sweating - Evaporation of water takes away heat energy from the surface of the skin.
63
What physiological changes occur when the body temperature is too low?
- Vasoconstriction - blood vessels near the surface of the skin constrict so less heat is radiated away.
- Shivering - Respiration allows muscles to contract. It is an exothermic process, so heat energy is released.
- Sweating stops
64
What gland controls many other glands in the body?
The pituitary gland.
65
Why is the pituitary gland considered a master gland?
It secretes a wide range of hormones, some of which may stimulate other endocrine glands.
66
What is the role of the thyroid gland in the endocrine system?
Secretes the hormone thyroxine - controls metabolism, heart rate and body temperature.
67
How does the pancreas respond when blood glucose levels are too high?
The pancreas secretes the hormone insulin. Insulin binds to receptors on the liver and muscles, causing excess glucose to be converted into glycogen and stored.
68
How does the pancreas respond when blood glucose levels are too low?
The pancreas secretes the hormone glucagon. Glucagon binds to liver cells, causing glycogen to be converted into glucose and released into the blood.
69
How can type 1 diabetes be treated?
- Insulin injections before meals allows glucose to be converted into glycogen.
- Limiting carbohydrate intake.
- Attempts using pancreas and pancreatic cell transplants; investigations into genetic engineering of pancreatic cells.
70
How can type 2 diabetes be treated?
- Following a carefully controlled diet.
- Doing regular exercise
- Losing Weight
- Use of drugs which increase insulin production and effectiveness
71
How can water be lost from the body?
- During exhalation via the lungs
- Sweating
- Urine
72
What ways are ions lost from the body?
- Sweating
- Urine
73
How are excess amino acids excreted from the body?
- Excess amino acids are deaminated in the liver to from ammonia.
- Ammonia is toxic therefore it is converted in urea.
- Urea is excreted from the body via sweat and urine.
74
How do the kidneys maintain the balance of water and other substances in the body?
- Filter blood in order to remove waste product.
- Selectively reabsorb useful molecules.
75
Full name of ADH and it's purpose?
- Anti-Diuretic Hormone
- It is found in the pituitary gland and it is a hormone that control the water levels in the body.
76
What does ADH affect the reabsorption of water in the kidneys?
- When the blood is too concentrated, the pituitary gland secretes more ADH
- ADH travels in the bloodstream to the kidney and increase the permeability of kidney tubules to water.
- More water is reabsorbed in the kidneys, resulting in a smaller volume of more concentrated urine.
77
Why is kidney failure dangerous?
- A build up of toxic molecules in the body
- Uncontrolled ion and water balance and cells being damaged as a result of osmosis.
78
Describe the events of the menstrual cycle?
- Uterus lining thickens and eggs begin to mature in the ovaries
- An egg is released from one of the ovaries so the uterus lining remains thick
- If the egg is fertilised, pregnancy may occur. If not, both the egg and the uterus lining are shed during menstruation.
79
What is ovulation?
Ovulation is the release of a mature egg from the ovaries, which occurs approximately every 28 day?
80
What are the 4 main hormones involved in the menstrual cycle?
- Oestrogen
- Progesterone
- Follicle Stimulating Hormones (FSH)
- Luteinising Hormone (LH)
81
What is the role of FSH in the menstrual cycle?
FSH is secreted by the pituitary gland. It controls the maturation of eggs within the ovaries (inside a follicle) and triggers the production of oestrogen by the ovaries.
82
What is the role of oestrogen in the menstrual cycle?
Oestrogen is produced by the ovaries and released due to the action of FSH - it causes the regrowth of the uterus lining. It triggers the product of LH and restricts the release of more FSH.
83
What is the role of LH in the menstrual cycle?
LH is produced in the pituitary gland as a result oestrogen. Its release triggers ovulation.
84
What is the role of progesterone in the menstrual cycle?
Progesterone is secreted from the follicle of the ovary. It sustains the uterus lining and inhibits FSH and LH.
85
How does the contraceptive pill prevent pregnancy?
- Inhibits FSH so eggs do not mature
- Prevents the development of the uterus lining so eggs cannot implant
- Increases the thickness of cervical mucus and it immobilises sperm cells.
86
What is a contraceptive patch?
- Contains both oestrogen and progesterone
- It is a patch that is placed onto the skin for 7 days at a time.
87
What is the IUS?
The intrauterine system is a small plastic device that is inserted into the uterus. It release progesterone which thickens cervical mucus and prevents the build up of the uterine lining.
88
What is the IUD?
The intrauterine device is a small copper containing device inserted into the uterus, which prevents the implantation of embryos.
89
How do fertility drugs increase the chance of pregnancy?
Many fertility drugs contain FSH- which stimulates oestrogen production and the maturation of eggs in the ovary. They also contain LH which triggers ovulation.
90
What is IVF?
In-vitro Fertilisation is a fertility treatment:
- Mother is given FSH and LH to stimulate the maturation of eggs and ovulation
- Eggs are fertilised using sperm in a laboratory to develop into embryos.
- 1 or 2 embryos are inserted into the mother's womb.
91
What is a tropism?
A tropism is the response of a plant to a specific stimulus.
92
What is phototropism?
Phototropism is the response of a plant's shoot or root to light.
93
What is gravitropism?
Gravitropism is the response of a plant's shoot or root to gravity.
94
What is Auxin?
Auxin is a hormone which controls the growth of a plant's shoots and roots. When auxin is unevenly distributed in a growing plant, the rate of growth will be unequal.
95
How do plant shoots show positive phototropism?
- One side of the shoot is in the light, causing auxin to move to the shaded side.
- at the shaded side, the cells are stimulated to grow - The shoot bends towards the light.
- As a result, photosynthesis can occur at a faster rate.
96
How do plant shoots show negative gravitropism?
In a horizontal shoot, auxin accumulates in the lower side due to gravity. Cells on the lower side of the shoot grow more, causing the shoot to bend away from the direction of gravity. As a result, more light is usually available for photosynthesis.
97
How do plant roots show positive gravitropism?
In a horizontal root, auxin accumulates in the lower side, causing cells to grow less. The rot bends in the direction of gravity as a result more water and nutrients are available to the plants roots.
98
What are the uses of auxins?
- Weedkillers since auxin causes cells to grow at a rapid rate, causing plant death.
- Rooting powder since auxins causes new plant to grow very quickly.
- Tissue cultures since auxin promotes growth of roots and shoots.
99
What are the uses of ethene?
Control of food ripening in the food industry - allows fruits to be ripened just before they are sold.
100
What are the uses of gibberellins?
- Termination of seed dormancy
- promotion of flowering
- Increase of fruit size
