B5 Flashcards
What is homeostasis
Maintaining a stable internal environment even when the external or internal environment changes
Why is homeostasis important
Cells need the right conditions to function properly otherwise they will denurture
What 3 things do control systems control
Body temp, blood glucose and water content
What are the three components of a control system that work together to maintain a steady condition
Receptors, coordination centre(brain,spinal cord and pancreas) and effectors
What makes negative feedback responsive
When something in the body is too high or low so it needs to be back to normal
What is the process of negative feedback
Receptor detects a stimulus (too high/ too low)
Coordination centre receives and processes information then organises a respond
Effector produces response which counteracts change and restores optimum level
What happens if effectors carry on producing a response in negative feedback
The level can change too much which the receptor detects and the process starts again
What does the nervous system allow humans to do
React to their surroundings and coordinate their behaviour
What does a receptor do
Detect a stimuli
What does an effector do
Respond to impulses and bring change
What are the two effectors and what do they do to bring change
Muscles contract
Glands secrete hormones
What are the two parts of the CNS
Spinal cord and Brian
What is the order of response in the nervous system
Stimulus
Receptor
Sensory neurone
Relay neurone (CNS)
Motor neurone
Effector
Response
What is a synapse
The gap between two neurones
How does the nerve system get past a synapse
Electrical impulse triggers a chemical (neurotransmitter) to diffuse from a high concentration to a low concentration across the gap which sets of a new electrical impulse in the next neurone
What is a reflex
A rapid automatic response to certain stimuli that don’t involve the conscious part of the brain
What do reflexes help prevent
Injuries
What is an example of a reflex
Bright light in eyes
Pupil automatically gets smaller so less light enters which prevents damage
What is a reflex arc
Passage of information in a reflex
What effector is used in a reflex
The closest muscle to produce a quick reaction as it takes less time to get to it and produce a response
What is a reaction time
Time taken to respond to a stimulus
What three things are reaction time affected by
Age
Gender
Drugs
What is the reaction time experiment
Person tested sits with arm on table ledge
Other person holds ruler vertically between thumb and finger -zero level with fingers
Let go without warning - person catches as quick as possible
Measure form top of thumb
Higher number = slower reaction time
Repeat test and calculate mean
What are the controls for the reaction time experiment
Same person
Same hand
Dropped from same height
What is a hormone
A chemical messenger sent in the blood
What do hormones control
Things that need constant adjustment
How are hormones secreted
By the endocrine glands
Are hormones long or short lasting
Long
What is the pituitary gland
Produces many hormones that regulate body conditions
Why is the pituitary gland called the master gland
It sends hormones to direct other glands to release hormones to bring change
What do the ovaries produce
Oestrogen for the menstrual cycle
What do the testes produce
Testosterone to control puberty and sperm production
What does the thyroid gland produce
Thyroxine to regulate the metabolism, heart rate and temperature
What does the adrenal gland produce
Adrenaline to prepare body for flight or fight response
What does the pancreas produce
Insulin to regulate blood glucose level
What is the difference between hormones and nerves
Nerves - fast, short time, precise area, from pain signals/ eyes
Hormones - slower, long time, general way, from shock
What is the computer reaction time
Person clicks the computer when a stimuli shows up on screen
Why is the computer reaction time experiment more precise and accurate
It erases human error, records in milliseconds(smaller resolution), removes the possibility that the person could predict when to respond as person could read testers body language so can anticipate it
What order are the menstrual cycle hormones released in
FSH
oestrogen
LH
progesterone
How is FSH part of the menstrual cycle
Produced in pituitary gland
Matures egg in ovary
Stimulâtes ovary to produce oestrogen
How is oestrogen part of the menstrual cycle
Produced in ovaries
Causes uterus lining to grow
Stimulates release of LH
Inhibits FSH
How is LH part of the menstrual cycle
Produced by pituitary gland
Stimulates release of egg at day 14(ovulation)
How is progesterone part of the menstrual cycle
Produced in ovaries by remains of follicle after ovulation
Maintains uterus lining for second half of cycle
Progesterone levels fall = uterus lining breaks down
Inhibits release of LH and FSH
How is oestrogen contraceptive
Inhibits FSH production so the egg can’t mature therefore egg production and development stop
No egg = no baby
How does progesterone become contraceptive
Stimulâtes production of thick mucus which prevents the sperm reaching the egg
What does the combine pill contain
Oestrogen and progesterone
Pros of combined pill
Over 99% effective
Cons of combined pill
Side effects(headaches, nausea)
Doesn’t protect against STDs
Pros of progesterone only pill
Fewer side effects but just as effective
What is the contraceptive patch
5 x 5cm patch stuck to skin that lasts for a week
Produces oestrogen and progesterone
What is the contraceptive implant
Inserted under skin in arm
Releases continuous progesterone which stops ovaries releasing eggs stopping fertilised eggs implanting into the uterus
Lasts for 3 years
What is a barrier for sex
Non-hormonal contraception stops sperm getting to the egg
What do condoms protect against that nothing else does
STDs
What is a condom
Worn over penis during sexual intercourse to prevent sperm entering the vagina
What is a female condom
Worn inside the vagina
What is a diaphragm
Shallow plastic cup that fits over the cervix to form a barrier
Used with spermicide
What is spermicide
Disables/kills sperm
What is womenfolk with using spermicide alone
Not as effective (70-80%)
What is sterilisation
Permanent procedure Cutting/tying the fallopian tubes or sperm duct
What are natural methods of contraception
Avoiding sexual intercourse when the women is most fertile
Not very effective
Popular when people things hormonal and barrier methods are unnatural
What is abstinence
Don’t have sexual intercourse
100% effective
What is contraceptive injections
Progesterone
Lasts 2-3 months
What is intrauterine device
T shaped device inserted into uterus to kill sperm and prevent implantation of fertilised egg
What does a plastic IUD do
Release progesterone
What does a copper IUD do
Prevent sperm surviving in the uterus
What is puberty
When your body starts releasing hormones that trigger secondary sexual characteristics
How is puberty in men
Testosterone produced by tested stimulates sperm production and facial hair
How is puberty in women
Oestrogen produced by ovaries stimulates breast growth, egged mature and menstrual cycle
What happens when the body detects too much glucose in the blood
Insulin secreted by pancreas
Glucose moves from blood into liver and muscle cells
Insulin makes liver turn glucose into glycogen
Blood glucose is reduced
What happens when the body detects too little glucose in the blood
Glucagon secreted by pancreas
Glucagon makes liver turn glycogen into glucose
Glucose released into blood by liver
Blood glucose increased
What removes glucose form the blood
Vigorous exercise
Normal metabolism
What puts glucose in the blood
Eating carbohydrates
What hormones does the pancreas secrete to control blood glucose levels
Insulin and glucagon
What does diabetes mean
You can’t control your blood sugar levels
What is type 1 diabetes
Pancreas produces little to no insulin so the blood glucose can rise and kill them
What do people with diabetes type 1 need
Insulin therapy which are injections of insulin throughout the day especially at meal times so glucose is removed quickly from the blood stopping blood level getting too high
What does the amount of insulin injected depend on
Diet and active levels
What do people with diabetes type 1 have to do
Limit carbohydrate intake and exercise regularly to take glucose out of blood
What is types 2 diabetes
When a person becomes resistant to their own insulin so their body cells don’t respond properly to the hormone causing their blood sugar to rise to a dangerous level
What increases the chance of developing diabetes type 2
Overweight
How to control diabetes type 2
Controlled diet and regular exercise
Explain the menstrual cycle
Day 1 - menstruation starts where the uterus lining breaks down for about 4 days
Day 4-14 - Uterus lining builds up again ready to receive fertilised egg
Day 14 - ovulation where the egg develops and released form ovary
Day 14-28 - wall maintained and if no fertilised egg by day 28, lining breaks down and cycle starts again
What is the fertility drug
Stimulates ovulation (FSH, LH)
What does it mean if people have low FSH levels
Eggs can’t mature or get released so no pregnancies
Pros of fertility drug
Helps people get pregnant when they can’t
Cons of fertility drug
Doesn’t always work
May have to do many times which is expensive
Too many eggs can be stimulated so multiple pregnancies like twins
What is IVF
When eggs get collect from women’s ovaries and fertilised in a lab with men’s sperm
Fertilised eggs grow into embryos in lab incubators
Once tiny balls of cells one or two transferred back into women’s uterus
What is intra cytoplasmic sperm injection
Sperm directly injected into egg if low sperm count
Why is FSH and LH given before an egg collection
To stimulate several eggs to mature so more than one egg can be collected
Pros of IVf
Gives infertile couple a child
Cons of ivf
Multiple births
Low success rate which is stressful and upsetting from multiple failures
Why are people against ivf
Unused embryos destroyed - destroying human life
Genetic testing before implanting- selection of preferred characteristics
Where is the adrenal gland
Above the kidneys
What is adrenaline released in response to
Stressful/Scary situations
What does adrenaline increase
Oxygen and glucose to cells in brain and muscles
Heart rate
How is negative feedback used to control hormone levels
It detects body has gone above/below normal level which triggers response to bring back to normal
Where is the thyroid gland
In the neck
What does thyroxine regulate
Basal metabolic rate which is the speed chemical reactions occur at rest
What does thyroxine stimulate
Protein synthesis for growth and development
What happens when thyroxine level is too high
TSH from pituitary gland is inhibited which reduces thyroxine therefore blood level falls back to normal
