B5- hormones and nervous system Flashcards
homeostasis
the regulation of internal conditions to maintain optimum conditions in response to changes
stimulus
a change in the environment
receptors
cells that detect changes in the environment
sensory neurone
nerve cells taking impulse from the receptor to the brain
motor neurone
nerve cells taking impulse from the brain to the body’s effectors
coordination centres
receive and process information from receptors
effectors
muscles or glands which bring about a response
reflex action
an automatic and rapid action not involving the brain
cerebral cortex
the outer part of the brain responsible for intelligence, language, memory and consciousness
cerebellum
controls balance, coordination of movement and muscular activity
medulla
controls unconscious activities such as heart rate and breathing rate
MRI
brain scanning technique
accommodation
the process of changing the shape of the lens to focus on near or distant objects
myopia
short sightedness
hyperopia
long sightedness
sclera
tough white outer covering of the eye
optic nerve
nerve going to the brain from the eye
cornea
clear section at the front of the eye- does most of the light bending
iris
coloured muscles around the pupils controlling light levels
pupil
hole in the iris that can change shape
ciliary muscles
Muscles that change the shape of the lens for focusing
lens
Clear ball that can change shape and focus light on the retina
Suspensory ligaments
Connects the lens to the ciliary muscles and can tighten to flatten the lens to focus on far objects
Retina
Layer of light sensitive receptors at the back of the eye connected to the optic nerve
Laser eye surgery
Using a laser to change the shape of the cornea and correct vision
Endocrine system
Consists of glands that release hormones into the blood to get to a target organ to cause a response
Pituitary
Master gland that controls many other glands and organs
pancreas
Small tree shaped gland which produces digestive enzymes as well as the hormones to control blood sugar
thyroid gland
Gland that produces thyroxine for control of the metabolism
adrenal gland
Gland that produces adrenaline for ‘fight or flight’ response
ovary
Gland that produces oestrogen and progesterone (menstrual cycle)
testes
Gland that produces testosterone
type 1 diabetes
When the pancreas does not produce enough insulin
type 2 diabetes
When the body cells no longer respond to insulin
insulin
Released from the pancreas in response to high blood glucose levels and causes glucose to be taken into cells and stored as glucogen
glucagon
Released from the pancreas in response to low blood glucose levels and causes glycogen to be broken down into glucose and released back into the blood
menstrual cycle
The 28 day cycle that readies the body for pregnancy, producing and releasing an egg, and building up the womb lining
Follicle stimulating hormone (FSH)
Hormone released by the pituitary gland. Causes maturation of the egg in the ovary.
oestrogen
Released by the ovaries. Stops FSH being released and stimulates LH to be released
Lutenising hormone (LH)
Hormone released by the pituitary gland. Causes the egg to be released from the ovary.
In vitro fertilisation (IVF)
Where egg cells are fertilised outside of the body with sperm cells then implanted into the woman to grown the baby
Contraception
Methods to prevent fertilisation
Abstinence
Refraining from sex completely or during fertile periods to avoid pregnancy
Barrier methods
Egg and sperm physically prevented from meeting (eg condom and diaphragm)
Hormonal methods
Hormones are used to interrupt the menstrual cycle and prevent egg release (eg the pill or implants)
Negative feedback
The automatic switching off of a system when it reaches the desired level eg FSh turns on oestrogen which turns off FSH
Vasoconstriction
When blood vessels supplying blood to the skin narrow and allow less warm blood to flow near the surface of the skin, which reduces heat loss
Vasodilation
When blood vessels supplying blood to the skin open and allow more warm blood to flow near the surface of the skin, which increases heat loss
Kidney
An organ that removes the toxin urea from the blood and keeps the water levels in the blood constant to avoid issues with osmosis
Deamination
The removal of the amine group on amino acids to form urea
filtrate
The liquid part of the blood that is pushed through the filter in the kidney with the useful solutes AND the waste
selective reabsorption
When the useful substances are reabsorbed back into the blood from the kidney tubules eg all the glucose
ADH
Hormone released from the pituitary gland which regulates the water concentration of the blood (don’t wee!- causes water to be reabsorbed and not go into urine)
kidney tubules
Long tubes in the kidney where the body quickly reabsorbs any water or nutrients it doesn’t want to end up in the urine
kidney dialysis
Using a machine to replace the cleaning and water balancing functions of failing kidneys
kidney transplant
Using a donor kidney to replace failing kidneys (kidneys can be taken from a living donor as you can survive on one)
tropisms
Plants response to the environment eg phototropism (light) and geotropism/ gravitropism (gravity)
auxin
Promotes rooting in cuttings
Can be used a weed killer
Used in tissue culturing
Is the hormone that controls tropisms
Gibberellins
Starts seeds germinating / ends seed dormancy Increases flower size
Increases fruit size
ethene
Promotes ripening of fruit Controls cell division
Stimulus
Receptors
Sensory neurone
coordination centres
effectors
r
describe the process of stimulus and response
ordinary nervous response:
NOTE: link this to the question dont just reel off the order.
memory aid- skinning really soft cats makes excellent rugs
- A stimulus reaches the body (eg a noise) and is detected by receptors
- Receptors send an impulse along the sensory neurone to the brain
- The brain makes a decision based on this information
- The brain sends an impulse along the motor neurone
- The motor neurone is connected to an effector (a muscle or gland)
- The effector causes the response
Reflex Nervous response:
Describe how a reflex system coordinates stimulus and response:
NOTE: link this to the question dont just reel off the order.
Reflexes are fast and automatic and are used to protect us from danger. They include examples such as taking your hand off a hot object. If a baby cant do it- it isnt a reflex
- A stimulus reaches the body (eg pain) and is detected by receptors
- Receptors send an impulse along the sensory neurone to the spinal cord
- A relay neurone in the spinal cord passes the impulse directly to the motor neurone
- The motor neurone is connected to an effector (a muscle or gland)
- The effector causes the response
describe the control of glucose in the body
-when you eat, the glucose level in the blood rises
-the pancreas responds to an increase in blood glucose levels and releases insulin which removes glucose from the blood storing it as glycogen in the liver and muscle cells
-as the glucose levels in the blood start to fall, the pancreas releases glucagon which causes glycogen to be broken up ans glucose released back into the blood
3 things
what does homeostasis control
-blood glucose concentration
-body temperature
-water levels
give three coordination centres
the brain
the spinal cord
the pancreas
why does homeostasis need to maintain optimal conditions
for enzyme action and all cell functions
what are the two automatic response systems
nervous responses and chemical responses
theres 5
list the receptor cells and state what stimulus they detect
eye- light
ear- sound
nose- chemicals in the air
mouth- chemicals in food
skin - touch, pressure, pain and temperature
what is a synapse
a gap between two neurones
describe what happens at the synapse
an impulse reaches the end of a neurone; neurotransmitter is released across the gap. it then diffuses across the synapse and when it reaches the next neurome this starts another impulse
what is accommodation
the process of changing the shape of the lens to focus on near or distant objects
how does the eye focus on distant objects
the ciliary muscles relax, the suspensory ligaments are pulled tight, the lens is then pulled thin and only slightly refracts light rays
how does the eye focus on near objects
the ciliary muscles contract, the suspensory ligaments loosen, the lens is tyen thicker and refracts light rays strongly
how do neuroscientists study the brain
studying patients with brain damage, electrically stimulating the brain and using magnetic resonance imaging (mri) scanning
what is an EEG
electroencephalogram, used to find problems related to electrical activity of the brain
describe what happens in vasoconstriction and vasodilation
-if the body temperature is too low, blood vessels constrict (vasoconstriction), sweating stops and skeletal muscles contract (shiver).
-if the body temperature is too high, blood vessels dilate (vasodilation) and sweat is produced from the sweat glands. both these mechanisms cause a transfer of energy from the skin to the environment.
what is the endocrine system composed of?
glands
what is a hormone
a chemical that is released from a gland in response to a change
how are hormones carried around the body?
in the bloodstream
which acts faster, the nervous system or the endocrine system
the nervous system
where is the pituitary gland
brain
what is the role of the pituitary gland
it secretes many hormones in response to changes in body conditions
name the hormones released by the pituitary gland
anti diuretic
thyroid
luteinising
follicle stimulating
prolactin
growth hormone
name the hormones that the pancreas releases
insulin and glucagon
what happens to the glucose in the blood when insulin is released?
glucose is removed from the blood and then converted to glycogen and stored in the liver and muscles
describe the role of glucagon in the regulation of glucose
glucagon is released when the blood glucose concentration is low and it stimulates the liver and muscles to convert glycogen into glucose
what type of diabetes is caused when the body cells no longer respond to insulin?
type 2
list advantages of kidney dialysis
-available to all kidney patients
-no need for immune suppressant drugs
list the disadvantages of kidney dialysis
-patient must limit their salt and protein intake between dialysis sessions
-expensive for the NHS
-regular dialysis sessions (up to 8 hours) impacts on the patients lifestyle
-risk of infection
list advantages of kidney transplants
-patients can lead a more normal life without having to watch what they eat and drink
-cheaper for the NHS overall
list the disadvantages of kidney transplants
-must take immune suppressant drugs which increase the risk of infection
-shortage of organ donors
-transplanted kidneys only last 8-9 years on average
-any operation carries risks
state the ways in which water is lost from the body?
lungs, urine, skin(sweat)
