Topic 7 - Animal Coordination, Control and Homeostasis Flashcards
(102 cards)
1
Q
What are hormones?
A
Chemical messengers sent in the blood, carried to parts of the body, but only affects particular cells in particular organs.
2
Q
What do hormones control?
A
Things in organs and cells that need constant adjustment.
3
Q
Where are hormones produced?
A
They arev produced in (and secreted by) various glands called endocrine glands, which make up your endocrine system.
4
Q
The Pituitary gland
A
Found in the brain, produces many hormones that regulate body conditions. Sometimes called the “master gland” because the hormones act on other glands, directing them to release hormones that bring about change.
5
Q
Thyroid Gland
A
Found in the neck, this produced thyroxine, which is involved in regulating thing like theRate of Metabolism, Heart rate and temperature
6
Q
Ovaries
A
Produces oestrogren, which is involved in the menstrual cycle
7
Q
Adrenal Glands
A
Produces adrenaline, used to prepare the “fight or flight”
8
Q
Testes
A
produces testosterone, which controls puberty and sperm production in males
9
Q
The pancreas
A
produces insulin, which is used to regulate blood glucose level.
10
Q
Comparison of Neurones and Hormones
A
Neurones: ———————- Hormones:
Very Fast action——————-Slower action
Act for a very short time ——–Act for a long time
Act on a very precise area.——Act in a more general way
11
Q
Will a quick response be Nervous or Hormonal?
A
Nervous
Some information needs to passed to effectors really quickly e.g. Pain or reflex. So Hormones would be too slow
12
Q
Will a slow response be Nervous or Hormonal?
A
Hormonal
For example, a flight or fight response leaves you feeling a bit wobbly afterwards as the hormones leave a longer effect.
13
Q
Adrenaline
A
- Release by the Adrenal Glands
- Prepares the body for “fight or flight” by activating processes that increase the supply of oxygen and glucose to cells
14
Q
How does Adrenaline increase Heart rate and blood pressure?
A
- Binds to specific receptors in the heart - causing the heart muscle to contract more frequently and with more force - Heart rate and blood pressure increase
15
Q
How does Adrenaline increase Respiration?
A
Once it increases blood flow to the muscles through binding receptors in the heart, The cells receive more oxygen ang glucose for increased respiration.
16
Q
How does Adrenaline increase Blood glucose level?
A
It binds to receptors in the liver. This causes the liver to break down its glycogen stores to release glucose. This increases blood glucose level, so there’s more glucose in the blood to be transported to cells
17
Q
What is hormone release controlled by?
A
Negative feedback
When the body detects that the level of a substance has gone above or below the normal level, it triggers a response to bring the level back to normal again.
18
Q
Thyroxine
A
- Released by the thyroid gland, regulates metabolic rate
- Negative feedback system keeps it at the right level
19
Q
Definition for metabolic rate
A
Speed at which chemical reactions in the body occur
20
Q
Negative feedback systme for thyroxine
A
- When blood thyroxine level is lower than normal, The hypothalamus is stimulated to release TRH.
- TRH then stimulates the pituitary gland to release TSH.
- TSH then stimulates the thyroid gland to release thyroxine so the blood thyroxine level rises back to normal
21
Q
Hypothalamus
A
A structure in the brain that triggers the release of horones in pituitary gland.
22
Q
What does TRH stand for?
A
Thyrotropin releasing hormone
23
Q
What does TSH stand for?
A
Thyroid stimulating hormone
24
Q
What is the menstrual cycle?
A
The monthly sequence of events in which the female body releases an egg and prepares the uterus (Womb) incase the egg is feritlised
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Stage 1 of the Menstrual cycle
**Menstruation starts**
The lining of the uterus breaks down and is released
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Stage 2 of the Menstrual cycle
**The uterus lining is repaired**
From day 4 to day 14, untill it becomes a thick, spongy layer full of blood vessels ready for an egg to implant there
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Stage 3 of the Menstrual cycle
| D14
**An egg develops and is released**
from the ovary (Ovulation) at day 14
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Stage 4 of the Menstrual cycle
**The lining is then maintained** for about 14 days, untill day 28. If no fertilised egg has landed on the uterus wall by day 28, the cycle starts again
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What are the 4 hormones that control the menstrual cycle?
FSH, Oestrogen, LH, Progesterone
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FSH role in the menstrual cycle
**Follicle stimulating hormone**
1. Released by the pituitary gland
2. Causes a follicle ( an egg and its surrounding cells ) to mature in one of the ovaries
3. Stimulates Oestrogen production
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Oestrogen role in the menstrual cycle
1. Released by the ovaries
2. causes lining of the uterus to thicken and grow
3. A high level stimulates an **LH surge**
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LH role in the menstrual cycle
**Lutienising hormone**
1. released by the pituitary gland
2. LH surge stimulates ovulation at day 14
3. Stimulates the remains of a follicle to develop into a *corpus luteum - which secretes progesterone*
33
Progesterone role in the menstrual cycle
1. Released by corupus luteum after ovulation
2. Maintains lining of uterus
3. Inhibits the release of FSH and LH
4. When the level of prog falls, and there is a low Oestrogen level, the uterene lining breaks down
5. A low progesterone allows FSH to increase, so the cycle starts again
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Clomifene Therapy for
- For women who are infertile because they dont ovulate ( or regulary )
- They can take a drug called Clomifene
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How does Clomifene Therapy work
Clomifene causes more FSH and LH to be released by the body, which stimulate egg maturation and ovulation. By knowing when the woman will be ovulating, the couple can have intercourse during this period to get the woman pregnant
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IVF
- Collecting eggs form a woman's ovaries and fertilising them in a lab using the man's sperm, these are then grown into embryos
- Once the embryos are tiny balls of cells, one or two of them are transferred to the woman's uterus lining to improve the change o pregnancy
- FSH and LH are given before egg collection to stimulate the production of eggs.
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What is IVF an example of?
**ART - Assisted Reproductive technology**
A fertility treatment that involves eggs being handled (and usually fertilised) outside of the body
38
How do kidneys help in homeostasis?
- Water content of blood cells needs to be controlled to help cells function normally
- Kidneys help to regulate water content by controlling how much water is re-absorbed and how much is lost in urine
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What happens if water blood concentration is too HIGH?
Water will move into body cells by osmosis. Too much water may cause the cells to burst
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What happens if water blood concentration is too LOW?
Water will move out of the cells by osmosis causing the cells to shrink
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What are the 3 main roles of the kidney?
- Removal of urea in the blood.
- Adjustment of ion levels in the blood
- Ajustment of water content in the blood
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Where is urea produced?
in the liver from the breakdown of excess amino acids
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How does the kidney remove urea and adjust ion and water conc levels?
Filtering stuff out of the blood under high pressure, then re-absorbing the useful things. Produces urine
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What are the filtration units in the kidneys?
Nephrons
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What happens in a nephron?
- The liquid part of the blood is forced out of the glomerus and into the bowmans capsule at high capsule ( Ultrafiltration)
- As liquid flows along nephron useful substances are re-absorbed from the tubules into the capillary network
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What does the liquid part of blood consist of?
water, urea, ions, glucose
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How does Ultra filtration in the kidneys work?
The liquid part of the blood is forced out of the glomerus and into the bowmans capsule at high capsule. Bigger molecules (e.g.protiens) and blood cells cant pass through the membranes and are not forced out.
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What useful substances are re-absorbed in the kidneys ?
- All glucose is selectively re-absorbed through active transport
- Sufficient ions are absorbed
- Sufficient water is absorbed according to the level of (hormone) ADH
49
What happens to the hormones what arent re-absorbed in the kidneys?
(e.g. urea, exxess water and ions) continues out of the nephron via the collecting duct. It then passes into the ureter and down the bladder as urine. Urine is released through the urethra
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What system is water content controlled by (Via kidneys)
A negative feedback system
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What hormone controlls the amount of water re-absored? How does this work?
ADH - Anti-Diuretic hormone
The brain monitors the water conent of the blood and instructs the *pituitary gland* to release ADH into the blood according to how much it needs, stopping the body from becoming de-hydrated
| Water gain = pituitary gland releases less ADH
52
What is a dialysis machine used for?
Patients with kidney failure cant filter their blood properly - the dialysis machine filters their blood for them
this has to be done regularly to keep dissolved substances at the right conc and to remove waste
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What is special about dialysis fluid?
it has the same conc of salts and glucosr as blood plasma which means those arent filtered out of the blood
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In dialysis machines what is the purpose of the selectively permeable barrier?
It is permeable to things like ions and waste substances, but not big molecules like protiens ( just like the membranes in kidneys). So the waste, plus exess ions and water from the blood move across the membrane into dialysis fluid. Cells and protiens stay in the blood
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What is the only cure for kidney disease?
Kidney transplants - these can however be rejected by the patients immune system - like a foreign body attacked by antibodies
56
What precautions are taken before kidney transplants?
- A donor witha tissue type that closely matches the patient is chosen
- A patient is given immuno-suppresants, so it wont attack the kidney
57
How can oestrogen be used as a contraceptive?
**It can prevent the release of an egg**
-> It typically stimulates the release of eggs, but if taken every day, it inhibits the production of FSH, and after a while egg development and production stop and stay stopped.
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How can progesterone be used to reduce fertility?
- It stimulates the production of a thick cervical mucus, which prevents any sperm getting through the entrance to the uterus (cervix) and reaching an egg
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What are some examples of hormonal contraceptives that contain both oestrogen and progesterone?
The combined pill (oral contraceptive) and the contraceptive patch (worn on skin)
60
What are 2 examples of hormonal contraceptives that contain just progesterone?
The mini-pill (oral contraceptive) and the contraceptive injection
61
What is a diaphram and what must it be used with?
Flexible, dome shaped device that fits over the opening of the uterus and are inserted before sex. This must be used with spermicide
| Other barrier contraceptives are condoms
62
What are the advantages and disadvantages of hormonal and barrier contraceptive methods?
**Hormonal____________Barrier**
More Effective____________Less Effective
No thinking____________Application needed each time
Unpleasant side effects____ None
Dont protect against STIs ____ Do
63
What is homeostasis?
Maintaining a constant internal environment
64
Why is homeostasis ( keeping conditions inside your body stable) Important?
Cells need the right conditions in order to function properly, including the right conditions for enzyme action.
-> it can be dangerous to health if conditions vary too much from normal levels
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What does your body have to do to maintain homeostasis?
Respond to both internal and external changes, whilst balancing inputs and outputs
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What are some examples of homeostasis?
**Osmoregulation (regulating water content)**
- Balance between water in (Drink,food,repiration) and water out (urine,sweat and breath)
**Thermoregulation (regulating body temperature)**
- Need to reduce when body is too hot, and icrease when environment is too cold
**Blood glucose regulation**
- Keep amount of glucose in blood steady
67
What does a negative feedback system mean?
If a condition changes away from the normal level, a response is triggered that counteracts the change
68
What is the rhyme to remember the hormones that control blood glucose levels?
**Insulin** takes blood glucose IN
**Glucagon** when blood glucose is GONE
69
How is glucose put into the blood?
Eating foods containing **carbohydrates** puts glucose into the blood from the **small intestine**
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What activitys remove glucose from the blood?
- **The normal metabolism of cells** removes glucose from the blood
- **Vigourous exercise removes much more glucose** from the blood
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Where is extra glucose stored and what is it stored as?
Glycogen in the liver and the muscles
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When glycogen stores in the liver and the muscles are full where is glucose stored?
Excess glucose is stored as lipid (fat) in the muscles
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What **organ** controlls the changes in blood glucose
Pancreas
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What happens when blood glucose is too high?
Blood with **too much glucose** comes in -> **Insulin is released/secreted by pancreas** -> Insulin and glucosey blood travel to liver -> Glucose moves from blood into liver and muscle cells **(Insulin makes liver turn glucose into glycogen)** -> Blood exits with reduced glucose
75
What happens when blood glucose is too **low**?
Blood with **too little glucose** comes in -> **Glucagon is released/secreted by pancreas** -> Glucagoney blood travel to liver -> Glucose is released into blood by liver **(Glucagon makes liver turn glycogen into glucose)** -> Blood exits with increased glucose
76
What is type 1 diabetes?
A condition where the pancreas produces little or no insulin -> Blood glucose can then rise to point where it kills the person
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How can a person with type 1 diabetes be treated?
Insulin therapy
-> Stops the level of glucose in the blood from getting too high and is a very effective treatment
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What does insulin therapy involve?
Injectin insulin into the subcutaneous tissue, where it will enter the bloodstream.
-> Often done at mealtime to make sure glucose from food consumed is removed from blood quickly
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What lifestyle factors should a person with type 1 diabetes control?
1) Limiting intake of foods rich in simple carbohydrates, i.e. sugars ( cause the blood glucose level to rise rapidly)
2) Taking regular exercise- removes excess glucose from blood
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What is type 2 diabetes?
A condition where the pancreas doesn't produce enough insulin or when a person becomes resistant to insulin
| causing blood glucose levels to rise
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What happens when a person becomes resistant to insulin?
Their body's cells dont respond properly to the hormone
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What does the correlation between obesity and type 2 diabetes mean?
obese people have an increased risk of developing type 2 diabetes
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What classifies people as obese?
BMI over 30
84
What is the formula for BMI?
Mass (kg) / Height2 (m)
85
Apart from obesity, what is also correlated to type 2 diabetes?
excess fat stores around the abdomen
| Indicated by waist-to-hip ratio
86
What is the formula for waist-to-hip ratio
Waist circumference (cm) / Hip circ (cm)
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What waist-to-hip ratio for men and women (individually) is associated with obesity?
Ratio above 1.00 for Men
and 0.85 for Women
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How can type 2 diabetes be controlled?
- Healthy diet, regulr exercise and loosing weight
- Medication such as insulin injections can also be used
89
What is thermoregulation?
The process your body uses to keep its internal temperature steady
90
What temperature do the enzymes in the body work best at?
37°C
-> Below this enzyme activity slows down
-> Above this enzymes start to denature
| 37°C is maintained by homeostasis and thermoregulation
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What controls thermoregulation?
the thermoregulatory centre in the hypothalamus
-> Detects change and causes a response in the skin
| Bros our thermostat
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How does the thermoregulatory centre in the hypothalamus detect change?
- It contains receptors that are sensitive to the blood temperature in the brain
- Receives impulses from receptors in the skin that rpovide information about the external temperature
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where are the receoptors that inform the hypothalamus about external temperature located?
Epidermis (outerlayer of skin)
Dermis (below epidermis)
94
What 3 things happen near the skin when you're hot?
1) Erector muscles relax, so hairs lie flat
2) Sweat
3) Vasodialation
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How is sweat used when you're too hot?
1) Lots of sweat is produced in the sweat glands in the dermis
2) The sweat is then released onto the surface of the skin through pores in the epidermis
3) When it evaporates it transfers energy from your skin to the environment, cooling you down
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what does sweat contain?
water and salts
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How does vasodialation cool you down?
1) Blood vessels close to the surface of the skin dialate
->Allows more blood to flow near the surface, so it can transfer more energy into the surroundings, which cools you down
98
What 4 things happen near the skin when you're too cold?
1) Erector muscles contract
2) Very little sweat is produced
3) Vasocontriction
4) Shiver
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How does erector mucles contracting heat you up?
This causes the hairs to stand on end to trap an insulating layer of air near the surface of the skin, which helps to keep you warm
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How does vasoconstriction heat you up?
Blood vessels near the surface of the skin constrict
-> Less blood flow near the surface = less energy transferred to the surroundings
101
What is the order and process of the kidneys?
| name locations
Glomerus --(filtration)--> Bowman's capsule
-> Proximal convulated tubule -> loop of Henle -> Distal convulated tubule (all reabsorbtion into capillaries -> renal vein)
-> collecting duct -> urine
102
# Kidneys
Between what 2 structures does filtration take place
Glomerus and bowman's capsule
