B5 Ai Flashcards
What is homeostasis?
The process of keeping the internal conditions of the body stable
Homeostasis involves maintaining optimal conditions for enzyme activity and overall bodily functions.
What are the three main parts of a control system for homeostasis?
- Receptors
- Coordination centres (including the brain, spinal cord, and pancreas)
- Effectors
These components work together to detect changes and initiate responses to maintain homeostasis.
How do control systems respond when the level of something in the body is too high?
The control system decreases the level
This is an automatic response to bring the level back to normal.
How do control systems respond when the level of something in the body is too low?
The control system increases the level
This ensures that bodily functions can continue effectively.
What is the role of receptors in a control system?
To detect a stimulus (change in the environment)
Receptors are the first component that senses changes and initiates the response process.
What is the function of the coordination centre in a control system?
To receive and process information from receptors
The coordination centre organizes an appropriate response based on the detected changes.
What does an effector do in a control system?
Produces a response to return the level to its optimum
Effectors can include muscles or glands that carry out the response.
True or False: Control systems for homeostasis require conscious thought to operate.
False
Control systems are automatic and function without the need for conscious thought.
Fill in the blank: A receptor detects a ______ and sends information to the coordination centre.
[stimulus]
Stimuli can include changes in temperature, blood glucose levels, and other environmental factors.
What happens after the coordination centre processes the information?
It organizes a response
This response is crucial for maintaining homeostasis.
Why is it important for the body to maintain steady internal conditions?
To ensure optimal conditions for enzymes and bodily functions
Fluctuations in internal conditions can disrupt metabolic processes and overall health.
What is the nervous system made up of?
Central Nervous System (CNS) and Peripheral Nervous System
The CNS consists of the brain and spinal cord.
What connects the CNS to the body?
Sensory neurones and motor neurones
Sensory neurones carry information to the CNS, while motor neurones carry information away from the CNS.
What are receptors?
Cells that detect stimuli
Different receptors detect different stimuli, such as sound in the ears.
What do sensory neurones do?
Carry information as electrical impulses from the receptors to the CNS
What do motor neurones do?
Carry electrical impulses from the CNS to effectors
What are effectors?
Muscles and glands that respond to electrical impulses
They bring about a change, such as muscle contraction or hormone release.
What is the role of the CNS in responding to stimuli?
It acts as a coordination centre that receives information and decides on a response
What is an example of a stimulus?
A cat approaching a bird
This stimulus can trigger a response in the bird.
What happens to the bird when it spots a cat?
The receptors in the bird’s eye are stimulated, and sensory neurones carry the information to the CNS
Fill in the blank: The passage of information between neurones occurs at _______.
Synapses
True or False: Reflexes are voluntary actions.
False
Reflexes are automatic and occur without conscious thought.
What is a reflex action?
An automatic response to a stimulus
Describe the process of a reflex action.
Stimulus -> Receptor -> Sensory neurone -> CNS -> Motor neurone -> Effector
What is an example of a reflex action?
A chef touches a hot stove and withdraws their hand
Name two types of effectors.
Muscles and glands
What is a synapse?
A synapse is where two neurones join together.
Synapses play a critical role in the transmission of electrical impulses between neurones.
How is an electrical impulse passed from one neurone to the next?
The electrical impulse is passed by chemicals.
These chemicals move across the synaptic gap to initiate a new impulse.
What is a reflex?
A reflex is an automatic response that does not require conscious thought.
Reflexes are also known as reflex reactions.
What is the purpose of reflexes?
To help prevent injury.
Reflexes allow for quick responses to stimuli.
What is a reflex arc?
The passage of information in a reflex from receptor to effector.
It involves sensory neurones, relay neurones, and motor neurones.
Where do the neurones in reflex arcs go through?
The spinal cord or an unconscious part of the brain.
This part of the brain is not involved in thinking.
What happens when a bee stings your finger?
The bee sting is detected by receptors, and impulses are sent along a sensory neurone to the CNS.
This initiates the reflex arc response.
What is the role of relay neurones in a reflex arc?
To pass on impulses from sensory neurones to motor neurones.
Relay neurones connect different types of neurones in the reflex pathway.
What is the effector in a reflex action when stung by a bee?
The effector is a muscle.
The muscle contracts to move your hand away from the bee.
Fill in the blank: Reflexes are useful for when you need to respond really _______.
quickly.
This characteristic is crucial for avoiding harm.
True or False: Reflex actions require conscious thought.
False.
Reflex actions occur automatically without the need for conscious thought.
What are hormones?
Chemical messengers sent in the blood
Hormones are released by glands directly into the bloodstream.
What are endocrine glands?
Glands that release hormones into the blood
They make up the endocrine system.
What is the function of hormones in the body?
They affect particular cells in particular organs (target organs)
Hormones are carried in the blood to various parts of the body.
What is the pituitary gland sometimes referred to as?
The ‘master gland’
It produces many hormones that regulate body conditions.
What role do pituitary hormones play?
They act on other glands to stimulate hormone release
This brings about change in the body.
What hormone do ovaries produce?
Oestrogen
It is involved in the menstrual cycle.
What does the thyroid gland produce?
Thyroxine
It regulates metabolism, heart rate, and temperature.
What hormone is produced by the adrenal gland?
Adrenaline
It prepares the body for a ‘fight or flight’ response.
What do testes produce?
Testosterone
It controls puberty and sperm production in males.
What hormone does the pancreas produce?
Insulin
It regulates blood glucose levels.
What are the main differences between nerves and hormones?
Nerves: fast action, short time, precise area; Hormones: slower action, long time, general way
Nerves act quickly and locally, while hormones have prolonged effects over broader areas.
True or False: Hormones control immediate life-threatening functions.
False
Hormones typically control functions like sexual development and blood sugar levels.
Fill in the blank: Hormones control many different _____ and cells in the body.
organs
Hormones are crucial for regulating various body functions.
How do hormones travel from their glands to their target organs?
Through the bloodstream
Hormones are released into the blood and carried to specific target organs.
What is the primary function of insulin?
Insulin reduces the blood glucose level
Insulin facilitates the uptake of glucose by cells for energy.
What triggers an increase in blood glucose levels?
Eating carbohydrates
Carbohydrates are broken down into glucose, which enters the bloodstream.
How does exercise affect blood glucose levels?
More glucose is removed from the blood
During exercise, muscle cells use more glucose for energy.
Which organ monitors and controls blood glucose concentration?
Pancreas
The pancreas regulates blood glucose by releasing hormones like insulin.
What happens when blood glucose concentration is too high?
The pancreas releases insulin
Insulin helps lower blood glucose levels by promoting cellular uptake.
What happens to glucose after it is removed from the blood?
It can be stored as glycogen
Glycogen is stored in the liver and muscle cells for future energy use.
Define Type 1 Diabetes.
Type 1 diabetes is where the pancreas produces little or no insulin
This condition can lead to dangerously high blood glucose levels.
What is a common treatment for Type 1 Diabetes?
Injections of insulin
Insulin injections help manage blood glucose levels post-meal.
Define Type 2 Diabetes.
Type 2 diabetes is where a person becomes resistant to their own insulin
The body still produces insulin, but cells do not respond effectively.
What lifestyle factor can increase the risk of developing Type 2 Diabetes?
Obesity
Being very overweight can contribute to insulin resistance.
How can Type 2 Diabetes be managed?
By eating a carbohydrate-controlled diet and exercising
Monitoring carbohydrate intake and regular physical activity can help control blood sugar levels.
Fill in the blank: Large amounts of glucose in the blood can damage _______.
organs like the heart
High blood glucose levels can lead to serious health complications.
True or False: The pancreas was once believed to be just a cushion.
True
This reflects historical misconceptions about the pancreas’s function.
What should you use to interpret a graph showing insulin’s effect on blood glucose levels?
Knowledge about graphs and insulin
Understanding the relationship between insulin and glucose can help in analyzing such graphs.
What is the monthly release of an egg from a woman’s ovaries called?
The menstrual cycle
At puberty, what starts to be released in the body?
Sex hormones
What do sex hormones trigger in the body during puberty?
Secondary sexual characteristics
What is an example of a secondary sexual characteristic in men?
Development of facial hair
What is an example of a secondary sexual characteristic in women?
Development of breasts
What causes eggs to mature in women?
Female sex hormones
What is the main reproductive hormone in men?
Testosterone
Where is testosterone produced in the male body?
Testes
What does testosterone stimulate in men?
Sperm production
What is the main reproductive hormone in women?
Oestrogen
Where is oestrogen produced in the female body?
Ovaries
What is oestrogen involved in?
The menstrual cycle
What are the four stages of the menstrual cycle?
- Lining of the uterus breaks down
- Lining of the uterus builds up
- Egg released
- Lining of the uterus maintained
What happens on Day 1 of the menstrual cycle?
Menstruation starts; the uterus lining breaks down
From which days does the uterus lining build up?
Day 4 to Day 14
What occurs on Day 14 of the menstrual cycle?
Ovulation; an egg is released from the ovary
What happens if no fertilised egg has landed on the uterus wall by Day 28?
The spongy lining starts to break down
What controls the menstrual cycle?
Four hormones
What does FSH (Follicle-Stimulating Hormone) do?
Causes an egg to mature in one of the ovaries
What does LH (Luteinising Hormone) do?
Causes the release of an egg (ovulation)
What hormones are involved in the growth and maintenance of the uterus lining?
- Oestrogen
- Progesterone
Fill in the blank: The menstrual cycle occurs once every _______.
28 days
True or False: The menstrual cycle has only three stages.
False
What is fertility?
Fertility is how easy it is for a woman to get pregnant.
What are contraceptives?
Contraceptives are things that prevent pregnancy.
What are hormonal contraceptives?
Hormones can be used in contraceptives — these are called hormonal contraceptives.
How do oral contraceptives work?
Oral contraceptives stop the hormone FSH from being released, which prevents eggs from maturing.
What is the effectiveness of oral contraceptives?
Oral contraceptives are over 99% effective at preventing pregnancy.
What are some side effects of oral contraceptives?
They can cause headaches and make you feel sick.
How do some hormonal contraceptives work?
They work by slowly releasing progesterone, preventing eggs from maturing or being released.
What is a contraceptive patch?
A small patch that is stuck to the skin and lasts one week.
What does the contraceptive patch release?
The contraceptive patch releases estrogen as well as progesterone.
What is a contraceptive implant?
An implant inserted under the skin of the arm that can last for three years.
How long does a contraceptive injection last?
Each dose lasts two to three months.
What is an intrauterine device (IUD)?
A T-shaped device that’s inserted into the uterus to stop fertilised eggs from implanting.
What is sterilisation in females?
Sterilisation involves cutting the fallopian tubes.
What is sterilisation in males?
Sterilisation involves cutting the sperm ducts.
What is natural family planning?
Natural family planning involves tracking the menstrual cycle to avoid pregnancy.
Fill in the blank: Hormones are needed for a woman to get pregnant, but they can also be used to _______.
[reduce fertility]
True or False: The contraceptive injection is a type of hormonal contraceptive.
True
Name two types of contraception that use hormones.
- Oral contraceptives
- Contraceptive patch
What is the purpose of contraception?
To prevent pregnancy.
What are non-hormonal contraceptives?
Types that don’t use hormones and stop the sperm from getting to the egg.
What is a barrier method of contraception?
A type of non-hormonal contraceptive that prevents sperm from reaching the egg.
What are condoms?
Worn over the penis during sexual intercourse and the only form of contraception that protects against sexually transmitted diseases.
What are female condoms?
Worn inside the vagina during sexual intercourse.
What is a diaphragm?
A shallow plastic cup that fits over the entrance to the uterus and must be used with spermicide.
What is the effectiveness of spermicide when used alone?
Only about 70-80% effective at preventing pregnancy.
What does sterilization involve in females?
Cutting or tying the fallopian tubes.
What does sterilization involve in males?
Cutting or tying the sperm ducts.
How long does sterilization last?
It is permanent and lasts for life.
What are natural methods of avoiding pregnancy?
Avoiding sexual intercourse during the fertile stage of the menstrual cycle.
Who tends to prefer natural methods of contraception?
People who think that hormonal and barrier methods are unnatural.
What is the effectiveness of natural methods of contraception?
Not very effective.
What is abstinence?
The only way to ensure that sperm and egg don’t meet is to not have intercourse.
What is the ultimate form of contraception according to the text?
Abstinence.
What might you be asked to evaluate in an exam regarding contraception?
The different hormonal and non-hormonal methods of contraception, including their pros and cons.
Fill in the blank: A diaphragm must be used with _______.
[spermicide]
