Homeostasis And Response Flashcards
What is homeostasis?
Maintaining a stable internal environment
Homeostasis is crucial for cell function and enzyme action.
Why is homeostasis important for cells?
Cells need the right conditions to function properly
This includes conditions necessary for enzyme activity.
What are the main components of automatic control systems in the body?
- Receptors
- Coordination centres
- Effectors
Coordination centres include the brain, spinal cord, and pancreas.
What role do receptors play in homeostasis?
Detect a stimulus (e.g., levels too high or too low)
Receptors initiate the feedback process.
What is the function of the coordination centre?
Receives and processes information, then organizes a response
It plays a critical role in regulating internal conditions.
What do effectors do in the homeostasis process?
Produce a response that counteracts the change and restores the optimum level
Effectors continue their response as long as stimulated by the coordination centre.
Fill in the blank: Homeostasis involves regulating conditions inside your body in response to changes in both _____ and _____ conditions.
[internal] and [external]
True or False: Homeostasis is a conscious process that requires active thought.
False
Homeostasis processes are automatic and occur without conscious thought.
How does negative feedback function in homeostasis?
Brings levels back to normal when they are too high or too low
Negative feedback involves a cycle of detection, processing, and response.
What happens if the level changes too much during the feedback process?
The receptor detects the change and negative feedback starts again
This prevents levels from straying too far from the ideal.
What is the primary function of the nervous system?
To detect and react to stimuli in the environment
This is essential for the survival of organisms.
What are the two main communication systems that evolved in multicellular organisms?
Nervous and hormonal communication systems
These systems allow for coordination among cells.
What does the Central Nervous System (CNS) consist of in vertebrates?
The brain and spinal cord
In mammals, the CNS connects to the body via sensory and motor neurones.
What are sensory neurones responsible for?
Carrying information as electrical impulses from receptors to the CNS
They play a crucial role in detecting stimuli.
What do motor neurones do?
Carry electrical impulses from the CNS to effectors
They initiate responses in the body.
What are receptors?
Cells that detect stimuli
Examples include taste receptors on the tongue and sound receptors in the ears.
What are effectors?
Muscles and glands that respond to nervous impulses
They bring about changes in the body.
How do muscles respond to nervous impulses?
By contracting
This is a direct response to stimulation from the CNS.
What is the role of glands in response to nervous impulses?
Secreting hormones
This helps regulate various bodily functions.
What is the function of the CNS as a coordination center?
To receive information from receptors and coordinate a response
It decides what action to take based on the stimuli detected.
In the example of the bird spotting a cat, what is the initial stimulus?
The cat skulking towards the bird
This prompts the bird to react.
What happens after the receptors in the bird’s eye are stimulated?
Sensory neurones carry the information to the CNS
This initiates the response process.
What is the final outcome of the response in the bird example?
The bird flies away to safety
This is the result of muscle contraction in response to the stimulus.
True or False: Only large animals like mammals and birds have complex nervous systems.
True
Simple animals like jellyfish rely on reflex responses.
Fill in the blank: The CNS sends information to the _______ to carry out the response.
effectors
Effectors are responsible for executing the response.
What is the connection between two neurones called?
Synapse
How is a nerve signal transferred across a synapse?
By chemicals that diffuse across the gap
What do the chemicals released at a synapse do?
Set off a new electrical signal in the next neurone
What are reflexes?
Rapid, automatic responses to certain stimuli that don’t involve the conscious part of the brain
What is an example of a reflex action involving bright light?
Pupils automatically get smaller to reduce light entering the eye
What hormone is released during a shock reflex?
Adrenaline
What is the pathway of information in a reflex called?
Reflex arc
Where do the neurones in reflex arcs go through?
Spinal cord or unconscious part of the brain
What is the role of the sensory neurone in a reflex arc?
Sends impulses from receptors to the relay neurone in the CNS
What happens when impulses reach a synapse between the sensory neurone and relay neurone?
Trigger chemicals to be released
What do relay neurones connect?
Sensory neurones to motor neurones
What happens when impulses reach a synapse between the relay neurone and motor neurone?
Chemicals are released and cause impulses to be sent along the motor neurone
What is the effector in a reflex reaction involving a hot pan?
Muscle
What is the final outcome of a reflex action when a muscle contracts?
Moves your hand away from the stimulus
True or False: Reflexes require conscious thought to occur.
False
Fill in the blank: The passage of information in a reflex arc goes through the _______.
Central Nervous System
What is reaction time?
The time it takes to respond to a stimulus, often less than a second.
What factors can affect reaction time?
- Age
- Gender
- Drugs
How can you measure reaction time using a ruler?
1) Sit with arm resting on a table.
2) Hold a ruler vertically between thumb and forefinger.
3) Let go without warning.
4) Catch the ruler as quickly as possible.
5) Measure the distance where it’s caught.
What does a higher number on the ruler indicate in the reaction time test?
A slower reaction time.
What should be done after the initial reaction time test?
Have a caffeinated drink, wait ten minutes, then repeat the test.
How is reaction time calculated after the ruler test?
By using the mean distance the ruler fell.
What variables should be controlled for a fair reaction time test?
- Same person to catch the ruler each time
- Same hand used to catch
- Ruler dropped from the same height
- No caffeine consumed before the test
What are the potential side effects of consuming too much caffeine?
Unpleasant side effects.
How can reaction time be measured using a computer?
By clicking the mouse or pressing a key as soon as a stimulus appears on the screen.
What advantage do computers have in measuring reaction time?
They provide a more precise measurement by eliminating human error.
True or False: Using a ruler for measuring reaction time allows the catcher to predict the drop.
True.
Fill in the blank: Reaction time can be affected by _______.
[key learning term]
What are hormones?
Hormones are chemical molecules released directly into the blood.
What is the primary function of hormones?
Hormones control things in organs and cells that need constant adjustment.
What are endocrine glands?
Endocrine glands are glands that produce and secrete hormones.
How do hormones differ from nerves in terms of speed?
Hormones have a slower action compared to nerves.
What is the duration of the effects of hormones?
Hormones tend to have relatively long-lasting effects.
What is the role of the pituitary gland?
The pituitary gland produces many hormones that regulate body conditions and is sometimes called the ‘master gland’.
What hormone does the thyroid gland produce?
The thyroid gland produces thyroxine.
What does thyroxine regulate?
Thyroxine is involved in regulating the rate of metabolism, heart rate, and temperature.
What hormone do ovaries produce?
Ovaries produce estrogen.
What is the function of adrenaline produced by the adrenal gland?
Adrenaline prepares the body for a ‘fight or flight’ response.
What hormone do testes produce?
Testes produce testosterone.
What is the role of testosterone?
Testosterone controls puberty and sperm production in males.
What hormone does the pancreas produce?
The pancreas produces insulin.
What is the function of insulin?
Insulin regulates the blood glucose level.
True or False: Hormones act on a very precise area.
False. Hormones act in a more general way.
Fill in the blank: If a response is really quick, it’s probably _______.
nervous.
Fill in the blank: If a response lasts for a long time, it’s probably _______.
hormonal.
What types of conditions do hormones generally control?
Hormones control conditions that aren’t immediately life-threatening, such as sexual development, blood sugar level, and water content.
Why is the pituitary gland referred to as the ‘master gland’?
Because it produces hormones that regulate other glands.
What are the two hormones involved in controlling blood glucose?
Insulin and glucagon
These hormones play critical roles in maintaining homeostasis of blood glucose levels.
What happens to glucose in the blood when carbohydrates are consumed?
Glucose enters the blood from the gut
This process occurs after eating foods containing carbohydrates.
How does vigorous exercise affect blood glucose levels?
It removes much more glucose from the blood
Exercise increases the uptake of glucose by muscle cells.
What can excess glucose be stored as in the body?
Glycogen
Glycogen is stored in the liver and muscles.
What is the role of the pancreas in blood glucose regulation?
It monitors and controls blood glucose levels
The pancreas uses insulin and glucagon in a negative feedback cycle.
What happens when blood glucose levels are too high?
Insulin is added
Insulin helps lower blood glucose levels by facilitating glucose uptake.
What happens when blood glucose levels are too low?
Glucagon is added
Glucagon increases blood glucose levels by promoting glycogen breakdown.
Fill in the blank: Insulin makes the liver turn glucose into _______.
glycogen
Fill in the blank: Glucagon makes the liver turn glycogen into _______.
glucose
What is Type 1 diabetes?
A condition where the pancreas produces little or no insulin
This can lead to dangerously high blood glucose levels.
What is the common treatment for Type 1 diabetes?
Insulin therapy
This typically involves multiple injections throughout the day.
What lifestyle changes are important for managing Type 1 diabetes?
Limiting intake of simple carbohydrates and regular exercise
These changes help control blood glucose levels.
What characterizes Type 2 diabetes?
Insulin resistance
The body produces insulin, but cells do not respond properly to it.
What is a major risk factor for developing Type 2 diabetes?
Being overweight
Obesity significantly increases the risk of insulin resistance.
How can Type 2 diabetes be managed?
Eating a carbohydrate-controlled diet and regular exercise
These strategies help maintain stable blood glucose levels.
What is the monthly release of an egg from a woman’s ovaries called?
The menstrual cycle
The menstrual cycle involves various stages, including menstruation, ovulation, and preparation for potential pregnancy.
What triggers the development of secondary sexual characteristics at puberty?
Sex hormones
These hormones include testosterone in men and estrogen in women.
What is the main reproductive hormone in men?
Testosterone
Testosterone is produced by the testes and stimulates sperm production.
What is the main reproductive hormone in women?
Estrogen
Estrogen is produced by the ovaries and is involved in the menstrual cycle.
What are the four stages of the menstrual cycle?
- Stage 1: Menstruation starts
- Stage 2: Uterus lining builds up
- Stage 3: Ovulation occurs
- Stage 4: Lining maintained until breakdown
Each stage corresponds to specific days in the cycle.
What hormone is produced in the pituitary gland and causes an egg to mature?
FSH (Follicle-Stimulating Hormone)
FSH stimulates the ovaries to produce estrogen.
What does estrogen do in the menstrual cycle?
- Causes the lining of the uterus to grow
- Stimulates the release of LH
- Inhibits the release of FSH
Estrogen plays a crucial role in preparing the body for potential pregnancy.
What is the function of progesterone in the menstrual cycle?
- Maintains the lining of the uterus during the second half of the cycle
- Inhibits the release of LH and FSH
Progesterone is produced by the remains of the follicle after ovulation.
What hormone stimulates the release of an egg at day 14?
LH (Luteinising Hormone)
LH is crucial for ovulation to occur.
True or False: Estrogen can be used as a method of contraception.
True
High levels of estrogen can inhibit FSH production, preventing egg development.
What contraceptive method contains both estrogen and progesterone?
The combined oral contraceptive pill
It is over 99% effective at preventing pregnancy.
What is the purpose of the contraceptive patch?
Releases estrogen and progesterone
The patch is a small device that lasts for one week.
What is a progesterone-only pill?
A contraceptive with fewer side effects than the combined pill
It is just as effective at preventing pregnancy.
What is an IUD?
An intrauterine device
It is inserted into the uterus to prevent implantation of a fertilized egg.
What is the role of condoms in contraception?
Prevent sperm from entering the vagina
Condoms are the only method that protects against sexually transmitted diseases.
Fill in the blank: A diaphragm must be used with _______ to be effective.
Spermicide
Spermicide disables or kills sperm.
What is sterilization in terms of contraception?
Cutting or tying the fallopian tubes or sperm duct
It is a permanent procedure with a small chance of reversal.
What is the natural method of contraception?
Avoiding intercourse on fertile days of the menstrual cycle
This method is not very effective compared to hormonal methods.
What is the only way to completely avoid pregnancy?
Abstinence
It involves not having sexual intercourse.
What should you consider when evaluating hormonal and non-hormonal contraceptive methods?
Pros and cons of each method
Understanding the effectiveness and side effects is crucial.
What hormone is used to stimulate ovulation in women with low ESH levels?
FSH (follicle-stimulating hormone) and LH (luteinizing hormone)
These hormones can be administered as part of fertility drugs.
What is one disadvantage of using hormones to increase fertility?
It can be expensive and may require multiple attempts.
Additionally, overstimulation can lead to multiple pregnancies.
What does IVF stand for?
In Vitro Fertilization
What is the process of IVF?
Collecting eggs from the ovaries and fertilizing them in a lab using sperm.
This may also include techniques like Intra-Cytoplasmic Sperm Injection (ICS).
What happens to fertilized eggs in IVF?
They are grown into embryos in a laboratory incubator.
One or two embryos are then transferred to the woman’s uterus.
What is the average success rate of IVF in the UK?
About 26%
What hormone is given before egg collection during IVF?
FSH (follicle-stimulating hormone)
It is used to stimulate several eggs to mature.
True or False: Multiple births from IVF can pose risks to the mother and babies.
True
What are some physical reactions women may have to fertility hormones?
Abdominal pain, vomiting, dehydration.
What ethical concerns are associated with unused embryos in IVF?
Some believe it is unethical to destroy embryos as they are considered potential human life.
What hormone is released by the adrenal glands in response to stress?
Adrenaline
What is the role of adrenaline in the body?
Prepares the body for ‘fight or flight’ by increasing oxygen and glucose supply.
It increases heart rate among other physiological changes.
What is thyroxine and where is it produced?
Thyroxine is a hormone produced in the thyroid gland.
It is made from iodine and amino acids.
What does thyroxine regulate in the body?
The basal metabolic rate and protein synthesis for growth and development.
How does negative feedback work in hormone regulation?
It triggers a response to return hormone levels to normal when they are too high or too low.
What hormone regulates the release of thyroxine?
Thyroid-stimulating hormone (TSH)
What happens when the level of thyroxine in the blood is too high?
The secretion of TSH is inhibited, reducing thyroxine release.
This helps bring thyroxine levels back to normal.
Name the gland that releases thyroxine.
Thyroid gland
