Homeostasis -fc 58 Flashcards
Define Homeostasis
regulation of body conditions whilst maintaining a stable internal environment in response to internal and external conditions
what is the process of temperature in negative feedback?
Temperature receptors detect the body temperature is too high, the thermoregulatory centre receives information and triggers affecters for factors. For example, sweat glands produce a response.
Why does the body need to obtain optimal conditions?
For optimal, enzyme action and cell function
What is the job of motor and relay neurone and sensory
sensory neuron transfer signals from receptor to CNS. The motor neuron transfer signal from CNS to effectors the relay neuron transfer signals from sensory neuron to motor neurone
List the pathway of a reflex arc
Stimulus, receptor, sensory neuron, relay neuron, motor neuron, effector, response
name the four parts of the brain
Cerebral cortex, cerebellum, Medulla hypothalamus
what is the function of the cerebral cortex?
It controls conscious activities such as memory vision and hearing and intelligence
What is the job of the cerebellum?
It controls muscle coordination and balance
what is the role of a Medulla?
It controls unconscious activities, such as breathing and heart rate
where is the medulla located?
Brain stem
name, the freeways scientist study the brain
- study people with brain damage
- electrically stimulated different parts of the brain
3.scan in the brain
explain three ways why treating the brain is so difficult?
Things can go wrong wrong such as infection.
It is in cased within the skull so it’s hard to access.
It is very complicated so hard to target with medication
describe the characteristics of the cornea
Transparent, no blood vessels, causes light to refracts
How does the iris react to bright light conditions?
The circular muscles contract and the radio muscles relax
How does the iris react to dark conditions?
bigger people circular muscles, relax, radio muscles contracts
Where should the lights be focused as it passes that
The fovea
what is the lens shape on a nearby objects?
Short and fat
what is the lens shape on a far away objects?
Long and thin
how do the ciliary muscles and suspensory ligament react to nearby objects?
Ciliary muscles contract, suspensory ligament loosen
lens become thicker and more curved - lights rays are refracted strongly
how do you the ciliary muscles and suspensory ligament react to distant?
Celery, muscles, relax, suspensory, ligaments tighten , lens becomes thinner and light refracted weakly
what lenses are used for longsighted people?
Convex lens
what lenses are used for shortsighted people?
Concave lens
why is the human body at 37 degrees
It is for optimum temperature for enzymes to function
where is the thermoregulatory centre located?
Brain
Where are temperature receptors found?
Blood vessels and skin
Name some methods to warm the body up
raise body hairs
Shivering
Constrict blood vessels nearest skin
Explain how shivering warms the body up
shivering involves muscle, relaxing, and contracting automatically. It requires a lot of energy from respiration in the process. It releases a lot of heat energy as waste.
explain VASO dilation
Blood vessels become wider, increasing the flow of blood in the skin capillaries
how does sweats keep us cool?
As sweat evaporates, it removes heat energy from the skin
Explain the job of glands (3)
Glands release hormones into the bloodstream. Hormones bind to specific cells that have correct receptors. This will bring about some change within the cells
Why is the pituitary gland known as the master gland
The hormones it releases controls what other glands do
What is the role of thyroxine
Found in the thyroid
regulates metabolism heart rate and body temperature
What is the role of adrenaline found in adrenal gland
Stimulates flight or fight response
What is one effect if the glucose levels are too high or low
damage tissues
cant carry out respiration
Explain the process of what happens in blood glucose is too high
Pancreas detects a change in the blood glucose levels
and releases insulin into the blood stream
Insulin binds to receptors on certain cells
Liver and muscles take in glucose and convert to glycogen
Blood glucose decrease
Explain what happens when the blood glucose levels are too low
Pancreas detects a change and secretes glucagon into the bloodstream.
Liver cells break down glycogen into glucose. It is then released into the bloodstream
Blood glucose levels increase
Describe 3 factors of type 1 diabetes
• Life long
• common in younger people
• Pancreas doesn’t release enough insulin
Explain type 2 diabetes
More common in older people
Tissues become resistant to own insulin
What increases the risk of type 2 diabetes?
Lack of exercise
poor diet
Define puberty
The period in which adolescents start to develop secondary sexual characteristics
Explain stage 1 of the menstruation cycle
• Menstruation
• bleeding breakdown of uterus lining
What happens in stage 2 of the menstrual cycle
Lining builds back up
What happens in stage 3 of the menstrual cycle
Egg is released form the ovaries
What happens in stage 4 of the menstrual cycle
maintaining lining of the uterus
What does Oestrogen don
Builds up lining
Stimulates release of LH
Job of Progesterone
Maintain lining of the uterus
inhibited LH AND FSH
Job of LH
stimulates release of egg
Job of FSH
Maturing of the egg stimulates oestrogen
Define 3 things that must occur for a woman to become pregnant
• Egg must be released from ovaries
• Sperm must reach and fertilise egg
• Fertilise egg implant into uterus lining
What two hormones does the pill contain
Oestrogen
Progesterone
How does oestrogen help as a contraceptive ?
Inhibit FSH production so eggs can’t mature
How does progesterone help with contraception
Stimulate production of mucus in the cervix so sperm can’t enter uterus
Explain the stages of IVF
- A woman is given FSH AND LH to stimulate her eggs to mature
- Eggs collected from women’s ovaries , sperm also collected
- Egg fertilised by sperm
- Fertilised eggs are left to grow as embryos in an incubator
- Once embryos are large enough transferred to uterus left to grow as a foetus
Explain ICSI
Sperm injected into an egg cell with a tiny needle
Why do people believe IVF is unethical?
• embryos could’ve had a potential life
• could lead to designer babies
Cons of IVF
multiple babies
abdominal pain
doesn’t always work
stressful
What is the job of the kidneys (3)
• Remove waste products
• Regulate water levels
• Regulate iron levels
What could happen when we have too much water
Cells can swell and burst
What happens to cells when we have too little water
Cells lose water and shrink
What is filtration
The Tubule absorbs anything small (glucose water ions)
What is selective reabsorbtion
reabsorb things they want to keep
What happens when water levels are too low
pituitary gland releases ADH
ADH tells kidneys to reabsorb water
What happens when water levels are too high
Hypothalamus stops sending signals to pituitary gland .
Kidneys produce more urine
Define deamination
The liver convert amino acids into lipids and carbs and stored as energy
Two ways ion can be removed
Sweating
kidneys
Blood passes through …. and out ….
renal arteries
renal veins
What happens when you have waste failures
waste substances build up in the bloodstream, unable to regulate water and iron levels
What are the three ways we lose water
exhale
sweating
urine
How do kidneys remove the waste product urea
• Blood enters kidney through artery and it contains urea
• The kidney removes urea and excess ions and water
• These leaves the kidney as URINE and is stored on bladder
• Blood leaves kidney through. vein
How does the body deal with excess amino acids
• The liver breaks down the excess amino acids and produced chemical ammonia (deamination)
ammonia converted to urea
If the levels of water falls in the blood, what does the pitruitary gland do
The pituitary gland releases ADH into bloodstream.
ADH travels to the kidneys and causes the kidney tubules to become more permeable to water
What is the effect of releasing ADH
less urine produced
amount of water in blood rises to normal level
What happens if the blood becomes too dilute
Pituitary gland stops releasing ADH.
The kidneys reabsorb less water into the blood
What is the effect of the Pituitary Gland stop releasing ADH
more urine is produced
Concentration of water returns to normal
How does Kidney dialysis work
The patients blood passes over a semi-permeable membrane
this allows urea ions and water through, not proteins
On the other side of membrane, dialysis fluid - norman concentrations of water and ions but no urea
urea diffuses from the bood by dialysis fluid
Why can kidney dialysis be inconvenient
visit hospital 3 times a week
controlled diet
Negatives of Dialysis
requires frequent treatment
controlled diet
expensive long term
Negatives of Dialysis
Shortage of kidneys
Patients have to take anti-rejection drug.
What is auxin
plant hormone at the shoot tip
How do shoots use the hormone auxin to grow towards the light
• Auxin triggers cell growth
• Light causes auxin to concentrate on the darker side of the shoot tip
• Auxin spreads down the shoot
• Cells on the darker side grows faster than the lighter side
• This causes the shoot to grow towards the light
Define gravitropism (geo tropism)
Plant roots grows towards the force of gravity
What does auxin do in roots
inhibits cell geowth
Explain gravitropism
Auxin produced in the root but gravity causes auxin to concentrate on lower side
Lower side grows more slowly than upper side this causes roots to grow towards force of gravity
What are the other chemicals plants use to regulate behaviour
Gibberellins
Ethene
What is the role of Gibberellin
starts germination of seeds
What is the role of ethene
controls cells division and ripening of fruits
What are auxins three main uses
Weed killers
Rooting powder
Promoting growth in tissue culture
What are the uses of Gibberellin
• end seed dormancy (force a seed to germinate earlier)
• encourage plants to flower
• used to make fruit grow larger
What are the uses of ethene
• Ripening
Describe the structure and function of the retina
• The retina is a light sensitive layer found at the back of the eye
• light stimulates retinal cells resulting in impulses being sent to the brain
Describe the structure and function of the the optic nerve
• Optic nerve connects the eye and the brain
• it carries impulses to the brain so that an image can be visualised
Describe the structure and function of the sclera
The sclera is the tough outer layer of the eye which protects internal structures
Describe the structure and function of the cornea
The cornea is the curved transparent layer at the front of the eye
it lets light into the eye and allows light to be focused onto the retina
Describe the structure and function of the iris
iris which controls the size of the pupil by contracting or relaxing . This allows the eye to adjust to bright and dim lighting
Describe the structure and function of the ciliary muscles and suspendiert ligaments
Hold the lens in place and control shape
What is accommodation
alteration or the lens shape in order to focus on near or distant objects
What is myopia (short sightedness)
usually occurs when the lens of the eye is too curved. As a result light is focused in the front of retina , images appear blurry
What do concave lens do
spread out light rays so they can be focused on retina
Explain Hyperopia (long-sightedness)
Lens of the eye is too flat
as a result light is focused behind retina so images appear out of focus
What do convex lens do
brings light rays together so they can be focused on retina
What are the two types of contact lenses
• Hard - rigid material , last long time must be kept sterile
• Soft - flexible material, lasts for a short time , comfortable
What is laser eye surgery and how is it used for myopia and hyperopia
myopia - lasers reduce the thickness of cornea so light is refracted less strong key
hyperopia- lasers alter the curve of the cornea so light is reflected correctly
What are the risks of lens replacement
retinal damage
cataracts
infections
Explain vasodilation when the body temperature is too high
blood vessels near the skin dilate more heat is radiates away
What is the role of the pituitary gland in the endocrine system
• Secretes human growth hormone - controls human growth
• Stimulates the thyroid gland
• Stimulates ovulation and the production of oestrogen in the ovaries
• Stimulates the production of sperm and testosterone in the testes
What does insulin injections before meals results in
glucose to be converted into glyocogen
What are the two main ways of treating kidney failure
dialysis
transplant
What are the two types of oral contraceptives
• combined contraceptive pill (oestrogen progesterone)
• mini pill (progesterone)
What is the contraception patch
• contains both oestrogen and progesterone
• a patch that is placed on the skin 7 days at a time
what is the contraceptive implant
a small rod inserted under the skin which releases hormone progesterone
What is the contraceptive injection
injection contains hormone progesterone
What is the IUS
small plastic device that is inserted into the uterus
releases progesterone- thickens cervical mucus and prevents build up of uterus lining
What is the IUD
small copper device inserted into uterus which prevents implantation of embryos
What is spermicide
chemical that kills or immobilises sperm cells
Two barrier methods of contraception
condoms
diaphragms - placed over crevix
What surgical methods of contraception are available
sterilisation - in males , sperm ducts are tied (vasectomy) and in females the oviducts are tied
Advantage of fertility treatment ?
allows infertile couples to have children
can store a woman’s eggs for later
What is negative feedback
a type of control where the body respond to an increase or decrease factor by returning it to optimum level
How is the release of thyroxine controlled by negative feedback
• levels of blood thyroxine falls - detected by receptors in the brain
• Pituitary gland releases more TSH
• more thyroxine releases by pituitary gland
• blood thyroxine level returns to normal
What are the effects of adrenaline
• Increase in heart rate and breathing rate
• dilation of pupils
• increased metal awareness
What is phototropism
response of a plants shoot or root to light
What is troposim
response of a plant to specific stimulus
what is gravitroposim
response of a plants short or root to gravity
How do plant shoots show positive phototropism
• one side of the shoot is in the light , causing auxin to move to shaded side
• at shaded side cells are stimulated to grow- shoot bends towards lights
• photosynthesis can occur at a faster rate
Disadvantages of fertility treatment
very expensive
multiple pregnancies
low success rate
How is temperature monitored by the body
• Thermoregulatory centre has receptors sensitive to blood temperature
• Skin has receptors sensitive to skin temperature- sends impulses to thermoregulatory centre
What ion does sweat have
sodium
