Combined 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.
