Separate Biology - B5 Homeostasis and Response Flashcards
Name the cells that detect stimuli (changes in the environment)
Receptors
What is homeostasis?
The regulation of internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
or
“Maintaining internal body conditions”
Why is homeostasis important?
To maintain optimum conditions for enzymes and all cell functions.
List three things that are controlled by homeostasis.
1) Blood glucose
2) Body Temperature
3) Water levels
What is the gap between two neurones called?
Synapse
What type of signal travels along neurones?
Electrical
What type of signal is transmitted across a synapse?
Chemical
Q.
a) What does CNS stand for?
b) What two organs make up the CNS?
a) Central nervous system
b) Brain and spinal cord
Name the organ from the CNS that is not involved in a reflex response.
Brain
List, in order, the neurones involved in a reflex response.
sensory neurone → relay neurone → motor neurone
What are the two types of effector?
Muscles and Glands
Put the following stages in order for a nerve response.
Effector / stimulus / response/ coordinator / receptor
- Stimulus
- Receptor
- Coordinator
- Effector
- Response
What is reaction time?
The time it takes for an organism to respond to a particular stimulus
Q. What is the name for the group of glands that produce hormones?
Q. How do the hormones secreted by these glands get to their target organ?
- Endocrine glands
- They travel in the blood
Compare nerve and hormones responses
- Hormones are slower and act in a more general way.
- Nerve responses are faster and act in a more precise way.
- Hormone responses act for longer than nerve responses.
- Hormones are chemical signals. Nerve responses are electrical signals.
a) What is the name of the ‘master gland’?
b) Where is the ’master gland’ located?
c) What is the job of the ’master gland’?
a) Pituitary gland
b) Brain
c) Stimulate other glands to secrete hormones
Can you locate the following glands on the human body?
adrenal / thyroid / ovaries / testes / pancreas / pituitary
Which part of the body coordinates blood glucose concentration?
Pancreas
Name the hormone that reduces blood sugar levels.
Insulin
Describe how blood glucose is controlled if it gets too high.
- The pancreas produces insulin.
- Insulin causes glucose to move from the blood into the cells.
- In liver and muscle cells, excess glucose is converted to glycogen for storage.
What is the role of FSH in the menstrual cycle?
Causes an egg to mature
What is the role of LH in the menstrual cycle?
Stimulates the release of an egg
What is the role of Progesterone in the menstrual cycle?
Maintains uterus lining
Q.
a) How does barrier method contraception work?
b) Name one type of barrier method contraception.
a) Prevents sperm reaching the egg
b) Examples include: condom, diaphragm e.t.c.
Name the hormone produced in the ovaries
Oestrogen
What is the name of the hormone produced in the testes?
Testosterone
On what day of the menstrual cycle is an egg released from the ovaries?
Day 14
What happens at ovulation?
An egg is released from the ovary
What type of diabetes is inherited?
Type 1 diabetes
Obesity is a risk factor for what type of diabetes?
Type 2 diabetes
What would a doctor prescribe for someone that has Type 1 diabetes?
Insulin injections
What would a doctor prescribe for someone that has Type 2 diabetes?
- Regular exercise
- Low carbohydrate diet
In which type of diabetes is no insulin produced?
Type 1 diabetes
In which type of diabetes is insulin still produced but is no longer effective?
Type 2 diabetes
Name two hormonal and two non-hormonal forms of contraception.
Hormonal: Any two from: Pill, injections, implant, patch, some intrauterine devices
Non-hormonal: Any two from: barrier methods e.g. condoms and diaphragms, spermicidal agents, abstaining, sterilisation and some intrauterine devices
Higher Q. Describe the stages involved in IVF.
- FSH and LH injections given to mother to stimulate maturation and release of multiple eggs.
- Eggs are collected from woman
- Sperm collected from the father
- Sperm injected into egg in laboratory (fertilisation)
- Eggs develop into embryo then one or two viable embryos implanted back into mother’s womb.
Higher Q. List three problems associated with IVF.
- Emotional and physical stress for mother
- Low success rates
- Risk of multiple births putting mothers and babies at risk.
Higher Q. Explain how blood glucose concentration is controlled if blood glucose levels are low.
- Pancreas produces glucagon
- Glucagon causes glycogen to be converted back into glucose
- Glucose is released back into the blood.
Higher Q. Where is adrenaline produced and what is its role in the body?
- Produced in the adrenal glands
- Involved in ‘fight or flight’ response to fear/stress
- Increases heart rate and delivery of oxygen and glucose to brain and muscles.
Higher Q. Where is thyroxine produced and what is its role in the body?
- Produced in the thyroid gland
- Helps control metabolic rate
- Important for growth and development
Higher Q. Explain how glucagon and insulin interact in a negative feedback cycle.
- If blood glucose levels are too high, the pancreas secretes insulin which removes glucose from blood into liver and muscle cells where it is stored as glycogen.
- Then, as a result, if blood glucose levels are now too low, pancreas secretes glucagon. Glucagon stimulates liver to turn glycogen into glucose. Glucose is then released back into the blood.
Higher Q. What hormones are used to increase a woman’s fertility?
FSH and LH
Higher Q. Explain how FSH, LH, oestrogen and progesterone interact in the menstrual cycle.
- FSH causes egg to mature and stimulate ovaries to produce oestrogen.
- Oestrogen stimulates release of LH from pituitary and inhibits release of FSH.
- LH stimulates release of the egg.
- Progesterone, produced by the ovaries, maintains uterus lining and inhibits the release of LH and FSH
Higher Q. Explain how thyroxine is controlled by a negative feedback process.
- If thyroxine levels are too high, release of TSH (thyroid stimulating hormone) from pituitary gland is inhibited to reduce thyroxine levels.
- If thyroxine levels are too low, TSH is released from the pituitary gland to increase thyroxine levels.
Separate Q. By what three ways is water lost from the body?
Separate Q. By what two ways are ions lost from the body?
Separate Q. By what two ways are urea lost from the body?
- Water: Lungs, Sweat, Urine
- Ions: Sweat, Urine
- Urea: Sweat, Urine
Separate Q. Explain the effects that osmotic changes have on cells.
- Osmotic changes will cause cells to gain or lose water.
- If they lose or gain too much water they won’t function properly.
Separate Q. Describe how the kidneys maintain the water balance inside the body
- By controlling the concentration of urine, which is controlled by ADH (anti-diuretic hormone).
- If water levels are too high, pituitary releases less ADH and less water is reabsorbed by kidneys (more dilute urine produced).
- If water levels are too low, pituitary releases more ADH and more water is reabsorbed by kidneys (more concentrated urine produced).
Separate Q. What’s one problem with losing ions, urea and water through the lungs or skin?
There is no control over how much is lost
Separate Higher Q. Describe how ammonia is produced in the body.
- Protein digestion results in excess amino acids
- In the liver, these amino acids are deaminated to form ammonia.
Separate Higher Q. How and why does the body get rid of ammonia?
- Ammonia is immediately converted into urea (and lost through urine e.t.c)
- Because ammonia is toxic, our body needs to get rid of it quickly.
Separate Q. Describe how the kidneys work
- Kidneys filter waste products out of blood by a process called filtration.
- The right amount of some ions, water and glucose are reabsorbed back into the blood by a process called selective reabsorption.
- Kidneys produce urine containing all the waste products.
Separate Q. Name three substances that are reabsorbed in the kidneys.
- Glucose
- Some ions
- Water.
Separate Higher Q. Describe how ADH controls the water level in the body when the blood becomes too concentrated.
- ADH is released by the pituitary gland.
- This causes more water to be reabsorbed back into the blood from the kidney tubules.
Separate Higher Q. Explain why the control of blood water levels by ADH is a negative feedback process.
Higher levels of ADH (to increase water reabsorption by kidneys) will then lead to inhibition of ADH (to decrease water reabsorption by kidneys).
Separate Q. Explain how dialysis works.
- Patient connected to dialysis machine for 3-4 hours.
- Patient’s blood flows through partially permeable membrane surrounded by dialysis fluid.
- Urea, ions and water diffuse across the membrane into the fluid.
- Dialysis fluid has the same concentration of ions, water and glucose as healthy blood to maintain appropriate concentration gradient between patient’s blood and dialysis fluid.
Separate Q. What are the advantages and disadvantages of treating kidney failure by mechanical device or transplant?
Mechanical devices (e.g. dialysis)
Advantages – Can keep a patient alive until kidney transplant.
Disadvantages – Each dialysis session takes several hours, may cause blood clots or infections, expensive for NHS.
Kidney transplant
Advantages – Long-term solution – only cure for kidney failure.
Disadvantages – Risk of rejection of donor kidney. Cheaper than dialysis. There are long waiting lists.
Separate Q. Give the name and the function of the following parts of the brain.
Separate Higher Q. Explain why it is difficult to treat brain damage and brain disease.
Because there are serious risks of causing further brain damage.
Separate Q. How have neuroscientists worked out the functions of the different regions of the brain?
- Studying patients with brain damage
- Electrically stimulating different parts of the brain
- Using MRI scanning techniques
Separate Q. Give the name and function of the following parts of the eye.
Separate Q. Name the sense organ containing receptors sensitive to light intensity and colour.
The eye
Separate Higher Q. Evaluate the benefits and risks of procedures carried out on the brain and nervous system.
Benefits: Some treatments such as electrical stimulation can lead to improved symptoms / better quality of life.
MRI and electrical stimulation can help scientists understand more about how the brain works.
Risk: Causing further brain damage (e.g. speech problems) or even death.
Separate Q. What does ‘accommodation’ mean in terms of eyesight?
The process of changing the shape of the lens to focus on near or distant objects.
Separate Q. Describe what happens to the ciliary muscles, suspensory ligaments and lens when focusing…
a) …On near objects
b) …On distant objects
a) Near Objects: Ciliary muscles contract, suspensory ligaments loosen, lens is thicker and refracts light rays strongly.
b) Distant Objects: Ciliary muscles relax, suspensory ligaments tighten, lens is thinner and only slightly refracts light.
Separate Q. Give the name for the following eyesight conditions:
a) Short sightedness
b) Long sightedness
a) Short sightedness = Myopia
b) Long sightedness = Hyperopia
Separate Q. Give two ways in which short and long sightedness are treated.
Any two from:
- Spectacles or contact lenses that refract light so the rays focus on the retina.
- Laser eye surgery – to change the shape of the cornea
- Replacement eye lens
Separate Q. Does the diagram below show myopia or hyperopia? How would you correct this?
- Myopia (short sightedness)
- Can be corrected using glasses with a concave lens.
Separate Q. Does the diagram below show myopia or hyperopia? How would you correct this?
- Hyperopia (long sightedness)
- Can be corrected using glasses with a convex lens.
Separate Q. Where in the body is the thermoregulatory centre?
• In the brain
Separate Q. Describe how the body responds to an increase in body temperature.
- The skin contains temperature receptors
- Nervous impulses are sent to thermoregulatory centre in brain
- Blood vessels dilate (vasodilation)
- Sweat is produced from sweat glands
- Energy is transferred from the skin to the environment.
Separate Q. Describe how the body responds to a decrease in body temperature.
- The skin contains temperature receptors
- Nervous impulses are sent to thermoregulatory centre in brain
- Blood vessels constrict (vasoconstriction)
- Sweating stops
- Skeletal muscles contract (shiver)
Separate Higher Q. Name the plant hormone responsible for initiating seed germination.
• Gibberellins
Separate Q. What is the plant response to light called?
Separate Q. What is the plant response to gravity called?
- Phototropism
- Gravitropism or geotropism
Separate Q. What is the name of the plant hormone that coordinates and controls growth in plants.
Auxin
Separate Q. Explain how auxin controls the growth of a shoot towards the light.
- Auxins collect on the shady side.
- Unequal distribution of auxin…
- …Causes unequal growth rates
- Growth stimulated on shady side
- Shoot bends towards light.
Separate Q. What effect does auxin have in…
a) … shoots
b) … roots
a) Stimulates growth
b) Inhibits growth
Separate Higher Q. Name the hormone that controls cell division and fruit ripening.
Ethene
Separate Higher Q. What three things can auxins be used for in agriculture and horticulture?
- Weed killers
- Rooting Powders
- Promoting growth in tissue culture
Separate Higher Q. How does using plant hormones as weed killers affect biodiversity?
- Auxin based weed killers are selective, only killing broad-leaved ‘weeds’ and not the crop.
- This results in all other plant varieties being killed, leaving only the crop plant.
- This results in lower biodiversity.
Separate Higher Q. What three things can gibberellins be used for?
- End seed dormancy/initiate germination
- Promote flowering
- Increase fruit size
