B5 Coordination And Control Flashcards
Homeostasis
Regulation of internal conditions in the body
Body systems responsible for homeostasis
Nervous system
Endocrine system
Nervous system
Response- rapid and short duration
Nature of message- nerve impulses electrical
Action- carried in nerves to specific location
Endocrine system
Response- slower but acts for longer
Nature of message- hormone chemical
Action- carried in blood to all organs, but affects target organ only
Structure of nervous system
Brain and spinal cord- CNS
Nerves leading to and from the brain and spinal cord- peripheral nervous system
Nerves
Consists of nerve cells(neurones) which are specialised to transmit messages as electrical impulses
Part that contains nucleus is cell body found in the CNS
Have extended shape to carry pulses from one part of the body to another. Have fine branches at the tips to communicate with other neurones.
Receptors
Cells that detect any changes in the environment. Receptors are grouped to form sense organs
Stimulus to response sequence
Stimulus Receptor Coordinator Effector Response
Reflex actions
Rapid automatic responses to a stimuli. To prevent us getting hurt
Reflex arc
Sensory neurone- transmits nerve implies from the receptor to the CNS
Relay neurone- in the spinal cord- transmits the impulses from the sensory to the motor neurone
Motor neurone- sends impulses from the CNS to the effector
Synapse
The gap between the neurones
How do impulses move from one neurone to the next
Chemical transmitter molecules are released into the synapse
Transmitter molecules diffuses across the synapse
Chemical transmitter molecules bind to the receptors
Channels in the next neurone opens
The nerve impulse is initiated in the next neurone
3 main regions of the brain
Cerebral cortex
Cerebellum
Medulla
Cerebral cortex
Highly folded outer layer concerned with: Consciousness Intelligence Memory Language
Cerebellum
Concerned with coordination of muscular activity
Medulla
Controls unconscious activities such as heartbeat and breathing
Electroencephalogram EEGs
Are used to monitor abnormal electrical activity in the brain, but can also be used in brain mapping
Transcranial magnetic stimulation TMS
A magnetic field changes the electrical activity in parts of the brain targeted
Changes to the patients behaviour occurs as different areas are stimulated to map the brain
MRI
Strong magnetic& radio waves produce detailed images Large tubes containing powerful magnets Detects the way hydrogen nuclei (protons) in water molecules respond to changes in magnetic and radio waves Produces greatest resolution of images Painless & safe Very expensive equipment Highly trained staff No ionising radiation
CT scans
X-rays and computer create detailed images of the body
Used to diagnose damaged tissue
Dye injected into body for better quality of the image
Only part of the body at a time
X-rays absorbed differently so compute used to build picture
Specially trained radiographers read images
X-rays= ionising radiation so long exposure causes cancer
EEGs
Small sensors attached over scalp to detect electrical signals
Highly trained specialists read changes and detect unusual activity
Detects epilepsy, fits and memory problems
No electricity put into body
Safe
Benefits of treating nervous system disorders
Kill cancer cells
Save/prolong life
Minimal damage to surrounding tissue
Stem cells&monoclonal antibodies
Risks of treating nervous system disorders
Affects normal cells as well Serious side effects Infection Stroke Chance it will come back Death May not work Rapidly dividing cells die May cause more damage
RP: investigating reaction time
Ruler drop test
Calculate reaction time with t= square root of 2d/a
t= time in seconds
d= distance traveled
a= acceleration as a result of gravity = 9.81 m/s^2
Cornea
Transparent region of the sclera at the front of the eye
Lens
Focuses light rays on the retina
Pupil
The hole in the centre of the iris that allows light to pass through
Iris
Has sets of muscles that control the size of the pupil and regulate the light reaching the retina
Suspensory ligaments and ciliary muscle
Change the shape of the lens to focus light rays on the retina
Optic nerve
Carries impulses from the retina to the brain
Retina
Made up of light sensitive receptor cells
Sclera
The tough outer layer of the eye
Cones
Receptor cells in the retina that perceive colour
Rods
Are responsible for vision at low intensity light.
More sensitive than cones by 1000x
In dim light
Racial muscles contract
The pupil becomes larger
Circular muscles relax
In bright light
Circular muscles contract
Pupil gets smaller
Reading muscles relax
Distant objects
Thin lenses
Only a slight refraction of light needed
Near objects
Thick lens refracts light rays strongly
Accommodation
The cornea is fixed in its shape
The lens however can change its shape to focus on objects that are located at different distances
Focusing on near objects
Ring of ciliary muscles contracts
Ring decreases in diameter
Reduction to diameter releases tens upon on Suspensory ligaments
Allowing lens to bulge and become thicker
Light rays are refracted more.
Short sightedness
Myopia Eyeball is too long for the strength of the lens Cornea is too sharply curved Corrected by concave lens Image falls short of the retina
Longsightedness
Hyperopia Lens is is too weak- not thick enough Eyeball is too short Cornea is not curved enough Image falls behind the retina Corrected by convex lens
Correcting vision
Use glasses or contact lenses
Have lazier eye surgery
Thermoregulatory centre
Centre has receptors which are sensitive to a change in the temperature of the blood circulating through it
Skin has temperature receptors that send nervous impulses to the thermoregulatory centre
Vadodilation
Temp is too high
Blood vessels near skin expand
Sweating increases
To cool down the body
Vasoconstriction
Blood vessels near skin get smaller
Sweating is reduce/stopped
Skeletal muscles contract and the body shivers
Sweating
Cooling through evaporation
As water molecules in sweat evaporate they take heat away from the skin
Negative feedback
The body being able to reverse changes to the body when they have happened
Endocrine system
Endocrine glands secrete homes directly into the blood.
Hormones
Described as chemical messengers. They circulate in the blood and produce an effect on target organs. Many hormones are large molecules.
They work on effectors and most take mins and hours to occur
Location of endocrine glands
Pituitary gland (brain) Thyroid gland (throat) Pancreas Adrenal glands Ovaries/testes
Insulin
Causes glucose in the blood to move into our body cells
When blood glucose concentration increases
Pancreas detects rise
Insulin secreted into blood
Liver turns glucose into glycogen
Blood glucose falls
When blood glucose concentration decreases
Pancreas detects fall
Glucagon secreted into blood
Liver turns glycogen into glucose
Blood glucose rises
Type 1 diabetes
Pancreas is unable to produce enough or any insulin
Body cells unable to take up glucose
Take insulin injections
10% of all diabetes
Person looses weight as body uses fat and protein
In untreated can cause kidney failure and death
Type 2 diabetes
Body cells lose sensitivity to the insulin being produced
Genetics
Glucose tolerance test
After 8-12 hours of no eating or drinking, blood glucose is measured. The person is then given glucose and blood is retested 2 hours later. If the persons tolerance to glucose is lowered the glucose will be above a certain level when retested.
Causes of diabetes
Genetics
Western life style
Obesity
Ethical considerations to diabetes
Should canteens/kitchens/manufactures use healthier ingredients
Social considerations to diabetes
Have a sugar tax so it makes theses foods more expensive
Where do we lose water from
Urine
Lungs as we breathe
Sweating
Why is water balance important
2% dehydration= thirsty and uncomfortable
5% dehydration= loose concentration
10-20% dehydration= life threatening
Deamination
Amino groups are removed as ammonia Ammonia is toxic to us Quickly converted into urea (less toxic) Urea is excreted from our bodies by our kidneys Can't store excess amino acids
Selective reabsorption
Blood is filtered- dissolved substances pass from the blood into the kidneys
Reabsorption- useful substances are absorbed back into the blood
Urine- contains urea, excess salts and excess water. Urine is taken to the bladder
ADH
Anti-diuretic hormone
Releases by pituitary gland in response to changes in the concentration of blood plasma
If there is more plasma then less water is reabsorbed by the kidneys (dilute urine) small amount of ADH is released by pituitary gland
If there is less plasma then more water is reabsorbed(concentrated urine) larger amount of ADH is released
Thyroid gland
Produces thyroxine which stimulate the body’s basal metabolic rate
Negative feedback for thyroxine system
Thyroid gland secretes thyroid hormone to target cell
Levels to high inhibits secretion of TSH
If levels are too low secretion of THS occurs
Dialysis
Blood remove from arm and circulated through kidney machine
Waste is filtered out through s partially permeable membrane
Blood returned to the arm
Needs to happen 3days a week taking about 4 hours
Kidney transplant
When a kidney is found from a donor who is a similar blood group as the patient
During the surgery the new kidney is connected to
a vein and artery
A tube that leads to the bladder where the urine is collected
After the kidney operation
The 2-3 hour complex surgery has a risk of rejection
Patients will need to take immunosuppressant drugs for the rest of their life although these drugs increase the risk of disease/infection
If transplant fails they will need to look for another one
Haemodialysis
Severe kidney failure
Don’t lose any blood
Clean blood
Can do it everyday
Peritoneal dialysis
Carry out themselves
Use peritoneal- thin membrane as filter
Absorbed into solution
Solution drained then solution replaced
Dialysis pros
Improved over the years
Greater independence
Better quality of life
Dialysis disadvantages
Experience sudden fall in blood pressure Watch out for infection Need treatment for rest of life Takes along time Patient become tired Machines are expensive
Transplant pros
More varied diet
Have a normal life style
Don’t have to go on dialysis
Transplants cons
Immunosuppressant drugs for rest of life Greater risk of infection,cancer,diabetes Make lifestyle changes May not last very long Can't have it if have heart condition Some people are too weak More donors needed Long waiting list Ethical issue: sold illegally, expensive,takes a long time
Secondary sex characteristics
Develop as our bodies produce reproductive hormones at puberty
Oestrogen
Main female reproductive hormone
Ovulation
Occurs every 28 days
Stimulates eggs to mature in the ovaries
Testosterone
Main male reproductive hormone
Produced by testes and stimulates sperm production
Menstrual cycle
1-5 menstruation uterus lining is shed
6-12 uterus lining starts to repair and grow again
13-15 ovulation egg is released from ovaries
16-28 uterus lining continues to thicken and egg dies if not fertilised
4 hormones that control the menstrual cycle
FSH follicle stimulating hormone(eggs mature in ovaries)
LH luteinising hormone (stimulate release of egg form ovaries)
Oestrogen and progesterone maintain the lining of the uterus
The roles of the hormones as the cycle progresses are:
FSH is secreted by pituitary gland
FSH causes the egg to mature in the ovaries
FSH stimulates the ovaries to produce oestrogen
Oestrogen inhibits further release of FSH and stimulates release of LH
LH triggers ovulation- the release of the mature egg from the ovary
Leads to secretion of progesterone by the empty follicle that contained the egg
Progesterone inhibits the release of LH and FSH
Progesterone maintains the lining of the uterus during the second half of the menstrual cycle, in the readiness for receiving a fertilised egg
Treating infertility
FSH and LH can be given a fertility drug
If it is successful it happens within 3 months
IVF conditions
More successful if the woman is: Younger Previously been pregnant BMI between 19-30 Low alcohol, caffeine intake and doesn't smoke
Stages of IVF
Woman is given FSH and LH to stimulate production of more eggs than normal in ovaries
Eggs are collected
Eggs mixed with fathers sperm in lab for 16-20 hours
Any embryos are allowed to develop for 5 days
1/2 embryos are selected and placed in the mothers uterus
Scientific and medical evaluation
Success rate isn’t high but is raising by 1% each year
Lots of premature births, still births and low weighted babies
Multiple births is possible
Adrenaline
Prepares us for fight or flight
Adrenal medulla
Combines endocrine and nervous system
Responds to nervous stimulation by releasing the hormone adrenaline
Adrenaline
Acts on various parts of the body such as the liver
Where it promotes the breakdown of glycogen into glucose and releases it into the bloodstream
Contraceptive methods
Either hormonal or barrier methods
Some people do natural planning
Natural planning
A woman’s time of ovulation is linked with:
Her menstrual cycle occurring at around 14 days
A slight increase in body temperature
Thinning of mucus secreted from the cervix
Barrier methods
Condom- a rubber polyurethane sheath that is rolled over the erected penis
Diaphragm- latex or silicone device that is put into the vagina to cover the cervix
Some women have surgery
Hormonal methods
Combined pill- oestrogen and progesterone
Progesterone only pill- thickens cervical mucus to prevent sperm entering it also inhibits the release of FSH and LH
IUDs are coils that prevent eggs being fertilised. Copper wound round them is toxic to sperm
Reliability of contraception
Abstinence is the most effect way
Most are between 92-99 when used perfectly
Condoms pros
Widely available
Can protect against transmitted diseases
Condom cons
May slip off
Must withdraw after ejaculation and not spill semen
Diaphragm pros
Put in before sex
No health risks
Diaphragm cons
Needs to be left in for hours after sex
Some people are sensitive to spermicide
UID pros
Works immediately
Can stay in place for 10 years (copper) 3-5 years (hormonal)
UID cons
Insertion may be uncomfortable
Periods may be longer or more painful
Tropism
The response of a plant by growing towards or away from a stimulus
Phototropism
The response to light
Growing towards the light is positive phototropism
Gravitropism
The growth response of a plant to gravity
Growing downwards is positive geotropism
Auxins
A type or hormone involved in the tropism of unequal distribution of hormones
Produced in the tips of shoots
Shoot tip responding to light
Plant is illuminated on one side
Auxin is redistributed.the shaded side grows more
Shoot tip grows towards the light
Meristems
Undifferentiated cells that can divide to produce new cells
Like stem cells for plants
Tissue cultures
Used to produce clones of plants
RP: the effect of light and gravity on the growth of germinating seeds
Seed planted in different conditions
The one with the most sunlight grew the most and had the greatest angle of curvature towards the light
Gibbellins
Promote plant growth/initiate plant growth even to dormant seeds
Ethene
Is a hydrocarbon released by bananas
It increases the rate of respiration making fruit ripen quicker
Ethane synthesis can be reduced by chilling or being sprayed by a chemical inhibitor
