Homeostasis and response (Seneca) Flashcards
Homeostasis describes all of the …
processes that happen in a cell or organism to maintain (keep) optimal conditions.
Homeostasis describes all of the processes that happen in a cell or organism to maintain (keep) optimal conditions. This is needed to respond to …
changes in the internal and external environment.
Because humans are organisms that live in a changing environment, we must regulate our body’s internal conditions to make sure …
our enzymes and cells function well.
If conditions are not optimal, then our enzymes can …
denature (change shape).
If conditions are not optimal, then our enzymes can denature (change shape).
This reduces their ability to …
catalyse (speed-up) metabolic reactions (chemical reactions in organisms).
Humans must regulate their body’s internal conditions to make sure that enzymes and cells function well. The conditions that need to be regulated are:
- Internal body temperature
- Carbon dioxide levels
- Water levels
- Blood sugar levels
- Urea concentration (in urine)
Control systems use both …
nervous and chemical responses.
Control systems use both nervous and chemical responses. Control systems are made up of three parts:
- Receptors
- Coordination centres
- Effectors (muscles or glands)
Effectors (muscles or glands) carry out responses to …
stimuli (events or things) that help to restore optimum levels.
Coordination centres receive and process …
information arriving from receptor cells.
Receptor cells can (function) …
detect changes in the environment
When our internal conditions are optimal, the body does not need to …
respond
If an internal condition changes and is no longer optimal, this ——— is detected and the body works to counteract (reverse) the change and return conditions to the optimum.
stimulus
If an internal condition changes and is no longer optimal, this stimulus is detected and the body works to …
counteract (reverse) the change and return conditions to the optimum.
Positive feedback is the opposite of negative feedback. It makes a small change …
even bigger.
An example of positive feedback in the body is the …
release of oxytocin (hormone), which increases the number of contractions during childbirth.
Lactic acid can cause …
muscle fatigue and soreness.
During anaerobic respiration glucose is broken down into …
lactic acid.
A person suffering from a condition called ———- cannot sweat.
anhidrosis
When a person sweats, heat is …
released which cools the body down.
Effectors carry out responses to ———— to help restore optimal levels.
stimuli
The nervous system protects organisms from …
harm by responding to changes in the environment.
The nervous system protects organisms from harm by responding to changes in the environment. It does this by …
coordinating communication between different parts of organisms.
The nervous system is made up of:
- The brain
- The spinal cord
- The neurones (nerve cells)
The brain is one of the components (parts) of the …
central nervous system (CNS).
The CNS coordinates …
the response of effectors.
Effectors are …
muscles or glands that act in response to a change in the internal or external environment.
The spinal cord is the other component (part) of the CNS. It is also important in …
coordinating the response of effectors to changes in the environment.
Neurones (nerve cells) carry …
electrical impulses (signals) between receptors, the central nervous system (CNS) and effectors.
What another name for neurones?
nerve cells
What are synapses?
Synapses are gaps between neurones and can be found at each junction of a reflex arc.
What does the CNS stand for?
Central nervous system
What are neurotransmitters?
Neurotransmitters are chemicals that diffuse across synapses and bind to receptors on the next neurone.
Define a reflex action.
A reflex action is an unconscious response
that allows a person to respond to a dangerous situation
automatically and rapidly via a reflex arc.
What are the components of a reflex arc?
- Stimulus.
- Receptor.
- Neurones.
- Effector.
- Response.
What type of signal are neurotransmitters?
Chemical
What terms describe a reflex action?
- unconscious
- fast
- automatic
Nerve impulses need to travel across synapses:
- Arrival at the synapse
- Passing on the impulse
The electrical impulse reaches the end of the neurone before the …
synapse.
The electrical impulse reaches the end of the neurone before the synapse.
This triggers …
the release of chemicals called neurotransmitters.
The neurotransmitters diffuse (move down a concentration gradient) across the synapse.The neurotransmitters bind to …
receptors on the next neurone.
The neurotransmitters diffuse (move down a concentration gradient) across the synapse.
The neurotransmitters bind to receptors on the next neurone.
The presence of the neurotransmitter causes …
the production of an electrical impulse in the next neurone.
At each junction of the ——— arc, there is a synapse.
reflex
Some examples of reflexes are:
- Sneezing
- Blinking
- Dropping hot objects
Reflex actions do not involve …
conscious thought.
The nervous system responds to stimuli (events or things) via a …
reflex arc.
The different parts of a reflex arc are:
- Stimulus
- Receptor
- Neurones
- Effector
- Response
A stimulus can be …
any change in the environment to which the body needs to respond.
The stimulus is detected by a …
receptor
Receptors are found …
all over the body.
Receptors are found all over the body.
They detect the …
change in the environment and initiate (start) a signalling process within the body.
The signal is picked up by a …
neurone (nerve cell).
There are three types of neurone (nerve cell):
- the sensory neurone
- the relay neurone
- motor neurone
The sensory neurone, which …
carries the signal in the form of an electrical impulse to the central nervous system (CNS).
The relay neurone (in the CNS) relays …
the electrical impulse from the sensory neurone to the appropriate motor neurone.
The motor neurone is another type of nerve cell that …
carries the electrical impulse from the CNS to an effector.
If the reaction time is reduced this means it takes …
less time to react.
—————— are factors that could affect human reaction time
Caffeine and exercise
Caffeine and exercise are factors that could affect human reaction time. Their effect can be tested by …
dropping and catching a ruler.
The steps in the practical procedure for reaction time are:
- Hold a ruler vertically from one end. The test subject should have their thumb and finger either side of the ruler at the 0cm mark.
- Drop the ruler. The subject should try to catch it between their thumb and forefinger as fast as possible.
- Note down the distance from the 0cm mark that the ruler travels before the subject catches it.
- Use a table to convert this distance into a reaction time.
- Repeat the experiment on a subject who has just had a coffee, or who has just done exercise.
- Compare reaction times.
In a ruler-drop experiment examining the effect of caffeine on human reaction time, what is the dependent variable?
the subject’s reaction time.
In a ruler-drop experiment examining the effect of caffeine on human reaction time, what is the independent variable?
whether or not the subject has had caffeine or exercised.
A synapse is a ——— between neurones.
junction
Neuromuscular junctions are a specialised type of …
synapse between a neuron and a muscle.
The brain is a very complex organ that …
controls all conscious and unconscious thoughts in order to keep an organism alive.
The brain is made up of …
millions of interconnecting neurones (nerve cells).
Different regions of the brain are responsible for …
coordinating (organising) different functions.
The brain is (describe) …
delicate, complex, and not well understood.
The brain is delicate, complex, and not well understood.
Therefore, the treatment of brain damage and brain disease is …
difficult
The brain is made up of ——— main parts.
three
The brain is made up of three main parts. They are:
- Cerebellum
- Medulla
- Cerebral cortex
Cerebellum is responsible for …
the muscle coordination.
The cerebellum is important for …
movement, posture, balance and speech.
Medulla is responsible for …
unconscious activities (e.g. breathing and heartbeat).
The Cerebral cortex is responsible for …
conscious thought (e.g. memory, language and intelligence).
————— has also allowed us to treat certain disorders of the brain.
Electrical stimulation
Electrical stimulation has also allowed us to …
treat certain disorders of the brain.
————- (scientists who study the brain) have been working for many years to understand how the brain works.
Neuroscientists
Because the nervous system communicates using electrical impulses, ————— is used to help treat conditions such as Parkinson’s disease (causes tremors).
electrical stimulation
By studying patients with brain damage, where part of their brain doesn’t function, neuroscientists have been able to …
link particular regions of the brain to particular functions.
MRI stands for …
Magnetic Resonance Imaging.
MRI scanners have allowed us to learn which …
areas of the brain are active during different activities, such as moving, speaking and listening.
What type of signals does the nervous system use to communicate?
Electrical impulses
Some of the techniques used in neuroscience are:
- Electrical stimulation
- MRI scanners
- Studying brain damage
Your retina is full of receptor cells, which are sensitive to …
both the brightness (light intensity) and the colour of light.
Retina scanning looks at the …
pattern of blood vessels in your retina to identify you
The Retina is Filled with …
receptor cells, which are sensitive to both the brightness (light intensity) and the colour of light.
Optic nerve transmits (sends) …
Visual information, in the form of electrical impulses, from the retina to the brain.
The cornea is …
The transparent frontal portion of the eye responsible for refracting light.
The iris controls …
pupil diameter and the quantity of light reaching the retina.
The pupil is …
hole in the centre of the iris, through which light passes.
Suspensory ligaments is a …
ring of fibres that connect ciliary muscles to the lens.
Ciliary muscles are a …
ring of smooth muscle that changes the shape of the lens to focus light.
What is the name of the muscle that can change the shape of the lens, which the eye uses to focus light?
Ciliary
How many key structures are found in the eye?
8
Key features of the eye:
- ciliary muscles
- iris
- suspensory ligaments
- pupil
- cornea
- sclera
- optic nerve
- retina
The sclera is the …
white of the eye and the opaque protective outer layer of the eye.
The cornea is the…
transparent frontal portion of the eye responsible for refracting light.
The optic nerve …
Transmits (sends) visual information (as electrical impulses) from the retina to the brain.
Accommodation is the process of …
changing lens shape in order to focus on an object as its distance from the eye changes.
The iris controls how our eyes adapt to different light levels by controlling the size of the pupil. If there is too much light, the iris …
decreases the pupil size to reduce the amount of light that reaches the retina.
Myopia happens when …
rays of light focus in front of the retina.
Hyperopia happens when …
rays of light focus behind the retina.
Both myopia and hyperopia can be treated using ————————-. Contact lenses and laser eye surgery can also correct these issues.
glasses fitted with lenses that refract light rays to allow the image to form on the retina
Both myopia and hyperopia can be treated using glasses fitted with lenses that refract light rays to allow the image to form on the retina. ——————— can also correct these issues.
Contact lenses and laser eye surgery
What is another name for long-sightedness?
Hyperopia
What is another name for short-sightedness?
Myopia
When our eyes focus on a close object, which structures undergo these changes?
- the lens thicken and rounded
- ciliary muscles contract
- suspensory ligaments loosen
Our body temperature needs to be kept as close to ——— as possible.
37°C
Receptors on the surface of the —— monitor the temperature at the surface of the body.
skin
Receptors in the ————— of our brain (called the hypothalamus) monitor the internal body temperature as blood flows through the brain.
thermoregulatory centre
Receptors in the thermoregulatory centre of our brain (called the hypothalamus) monitor …
the internal body temperature as blood flows through the brain.
Our body temperature needs to be kept as close to 37°C as possible. If your body is too hot:
- Sweat is released from sweat glands under the skin.
- Hairs lie flat.
- Blood vessels dilate to allow more blood to enter capillaries that pass close to the skin surface (vasodilation).
Our body temperature needs to be kept as close to 37°C as possible. If your body is cold:
- Muscle contractions increase, causing shivering.
- Hairs stand on end.
- Blood vessels constrict to reduce blood flow in capillaries (vasoconstriction).
—— means that something is related to blood vessels.
Vaso
Vaso means that something is …
related to blood vessels.
Vasodilation means …
Blood vessels dilate to allow more blood to enter capillaries
Vasoconstriction means …
Blood vessels constrict to reduce blood flow in capillaries
Sweat glands release water, which covers the …
skin
Sweat glands release water, which covers the skin.
Heat energy from the body is transferred to this …
water and, when it has enough energy, it evaporates.
Sweat glands release water, which covers the skin.
Heat energy from the body is transferred to this water and, when it has enough energy, it evaporates.
As it evaporates, it …
takes the heat energy with it. This lowers the average temperature of the body.
When we are too cold, muscles start to …
contract automatically. This makes us shiver.
When we are too cold, muscles start to contract automatically. This makes us shiver.
This process requires …
energy, which is generated through respiration.
When we are too cold, muscles start to contract automatically. This makes us shiver.
This process requires energy, which is generated through respiration.
Respiration produces …
heat, which warms us up.
When we are too cold, the hair erector muscle …
contracts, causing the hair to stand on end (which pull on the skin giving you goosebumps).
When all the hairs are standing on end, they …
trap an insulating layer of air around the body.
When we are too hot, the hair erector muscle …
relaxes, causing the hair to lie flat.
What is the technical term for body temperature control?
Thermoregulation
In what region of the brain are the receptors that detect internal body temperature?
Thermoregulatory centre
When we are too cold, muscle ———- increase, causing us to shiver.
contractions
The endocrine system coordinates the …
body’s response to changes in the environment using chemical messengers (hormones).
The optic nerve transmits visual information from the 1. to the 2.
- retina
- brain.
Hormones are released by ——– into the bloodstream, where they travel to target organs.
glands
Hormones are released by glands into the ————-, where they travel to target organs.
bloodstream
The ovaries produce oestrogen, which …
controls puberty and is one of the main hormones in the regulation of the menstrual cycle.
The ovaries produce ———–, which controls puberty and is one of the main hormones in the regulation of the menstrual cycle.
oestrogen
The ———- produce oestrogen, which controls puberty and is one of the main hormones in the regulation of the menstrual cycle.
ovaries
The ——— produces insulin and glucagon, both of which are involved in regulating blood glucose levels.
pancreas
The pancreas produces —————–, both of which are involved in regulating blood glucose levels.
insulin and glucagon
The pancreas produces insulin and glucagon, both of which are involved in …
regulating blood glucose levels.
The ——– are situated above each kidney.
two adrenal glands
The two adrenal glands are situated …
above each kidney.
Adrenal glands produce ———–, which triggers the ‘fight or flight’ response when an organism is presented with a dangerous situation.
adrenaline
Adrenal glands produce adrenaline, which …
triggers the ‘fight or flight’ response when an organism is presented with a dangerous situation.
————- produce adrenaline, which triggers the ‘fight or flight’ response when an organism is presented with a dangerous situation.
Adrenal glands
Thyroid gland is in …
our neck .
Thyroxine regulates …
our metabolism, heart rate and temperature.
Thyroid gland releases …
thyroxine.
Pituitary gland is the ——————- or “master gland”.
main endocrine gland
Pituitary gland is the main endocrine gland or “——————-“.
master gland
Pituitary gland is found in the brain and is linked to the …
hypothalamus (part of the brain that receives signals from receptors).
Pituitary gland is found in the —– and is linked to the hypothalamus (part of the brain that receives signals from receptors).
brain
The pituitary gland releases hormones in response to …
changes detected by the hypothalamus
The pituitary gland releases hormones in response to changes detected by the hypothalamus.
Lots of these hormones trigger …
other glands to release more hormones.
The testes produce testosterone, which …
controls puberty and sperm production.
The testes produce —————, which controls puberty and sperm production.
testosterone
The ———– produce testosterone, which controls puberty and sperm production.
testes
There are lots of different endocrine glands:
- Testes (male only)
- Pituitary gland
- Thyroid gland
- Adrenal glands
- Pancreas
- Ovaries (female only)
Why is the pituitary gland often called the “master gland”?
Many hormones released by the pituitary gland cause other glands to release hormones.
The central nervous system (CNS) is different to the endocrine system in a few key ways: (8)
Endocrine (hormonal) system:
- Triggers a slower response.
- Uses chemical messengers that are carried by blood.
- Response can be long-lasting.
- Can act on large areas of the body.
Central nervous system (CNS)
- Triggers rapid response.
- Uses electrical signals that are carried by neurones.
- Response is very short.
- Acts on a very precise part of the body.
Endocrine (hormonal) system
triggers a ———– (time) response.
slower
Endocrine (hormonal) system uses …
chemical messengers that are carried by blood.
Endocrine (hormonal) system response can be ———–lasting.
long
Endocrine (hormonal) system can act on ——- areas of the body.
large
Central nervous system triggers ——- (speed) response.
rapid
Central nervous system uses …
electrical signals that are carried by neurones.
Central nervous system response is (length) …
very short.
Central nervous system acts on a ———— part of the body.
very precise
Thyroxine is the main hormone secreted (released) by the thyroid gland. It increases the …
basal (resting) metabolic rate.
Thyroxine is responsible for ———————of young animals.
regulating the growth and brain development
Production is regulated by a ————–. This allows the body to maintain a fairly constant concentration of thyroxine in the blood.
negative feedback loop
Production is regulated by a negative feedback loop. This allows the body to ———————– of thyroxine in the blood.
maintain a fairly constant concentration
When the concentration of thyroid hormones, such as thyroxine, in the blood is low, the production of thyroid-stimulating hormone (TSH) is ——-. This stimulates the secretion of thyroxine by the thyroid gland.
increased
When the concentration of thyroid hormones in the blood is high, TSH production is …
decreased.
Adrenaline enlarges the air passages of the lungs and alters metabolism in order to …
boost the delivery of oxygen and glucose to the brain and the muscles.
Adrenaline —————————— in order to boost the delivery of oxygen and glucose to the brain and the muscles.
enlarges the air passages of the lungs and alters metabolism
In times of fear or stress, adrenaline is part of the so-called ‘fight or flight’ response, preparing the body to …
move and think quickly in response to danger.
In times of fear or stress, adrenaline is part of the so-called ‘———————–’ , preparing the body to move and think quickly in response to danger.
fight or flight response
Adrenaline increases heart rate and blood pressure, and dilates …
the pupils in our eyes.
Adrenaline increases ————————- , and dilates the pupils in our eyes.
heart rate and blood pressure
It is important for an organism to keep its blood glucose levels within a —— range.
small
If blood glucose levels are too high, this can have a ————- impact on osmosis (movement of water between cells) by affecting concentration gradients.
negative
Glucose is important for …
respiration.
Respiration releases the energy needed by …
every living cell.
If there is not enough glucose, an organism cannot produce enough …
energy.
which hormones released by the pancreas to control blood glucose levels?
- glucagon
- insulin
which organs helps to restore our glucose levels to normal when they fluctuate ?
liver
Diabetes sufferers are not able to control their blood glucose levels. There are two types of diabetes:
- Type 1 diabetes
- Type 2 diabetes
In type 1 diabetes, sufferers are unable to produce enough …
insulin.
In type 2 diabetes, sufferers can still produce insulin, but …
their body no longer responds to it.
Type 1 diabetes develops during …
childhood.
We do not know what causes Type 1 diabetes, but we think that the …
body’s immune system attacks the pancreas cells.
The main treatment for diabetes is to inject insulin when …
blood glucose levels rise too high.
The main treatment is to inject insulin when blood glucose levels rise too high.
Sufferers can also …
manage their diet and exercise regularly to keep blood glucose levels as steady as possible.
In type 2 diabetes, Because the body no longer responds to insulin, injecting insulin will not help.
Instead, sufferers must …
manage their diet and exercise regularly to keep blood glucose levels steady.
Type 2 diabetes usually develops …
later in life.
————————— are recognised as two of the primary risk factors of type 2 diabetes.
Old age and being overweight
Water levels in the body must be kept relatively constant to control the …
amount of water and ions diffusing into and out of cells.
Water levels in the body must be kept relatively constant to control the amount of water and ions diffusing into and out of cells. Many factors can disrupt this balance :
- Illness
- Eating too much salt
- Sweating
- Exhalation
Illnesses that cause fever, vomiting or diarrhoea can result in …
dehydration (the blood’s water concentration is too low).
Eating too much salt can make the …
blood ion concentration too high.
——————- are all lost in sweat.
Water, ions and urea
Water in the lungs leaves the body in the …
person’s breath.
The kidneys are important for homeostasis. They control the …
water and ion levels in the blood.
The volume of water in the blood is monitored by …
the hypothalamus in the brain.
The body’s ion levels must be kept relatively constant to control …
osmosis and diffusion between cells in the body.
The kidneys are important for homeostasis. What do they control?
- excess water levels
- ion levels
Urea needs to be removed from the body because it is toxic. When there is too much urea in the bloodstream, it can …
harm cells and tissues.
Urea needs to be removed from the body because it is …
toxic
Urea is formed when …
the digestion of protein results in an excess of (too many) amino acids, which can’t be stored in the body.
In the liver, these amino acids undergo a process known as deamination, and the waste product is …
ammonia
In the liver, these amino acids undergo a process known as ————-, and the waste product is ammonia.
deamination
In the ————, these amino acids undergo a process known as deamination, and the waste product is ammonia.
liver
The ammonia is then converted into ——— and must be excreted from the body as urine.
urea
The ammonia is then converted into urea and must be excreted from the body as …
urine
Name two uncontrolled ways in which water is lost:
- breathing
- sweating
Each kidney contains ———————— called nephrons.
millions of very small structures
Each kidney contains millions of very small structures called …
nephrons
Each kidney contains millions of very small structures called nephrons. There are two stages in the process of urine production :
- Ultrafiltration
- Selective reabsorption
During ultrafiltration, the blood is filtered and all ————- move into the nephron tubule.
water, Urea and salts
During ultrafiltration, the blood is filtered and all water, urea and salts move into the …
nephron tubule
During ultrafiltration, The blood is filtered and all water, urea and salts move into the nephron tubule.
Blood cells and proteins remain in the blood as …
they are too big to move across the capillary walls.
During ultrafiltration, The blood is filtered and all water, urea and salts move into the nephron tubule.
——————- remain in the blood as they are too big to move across the capillary walls.
Blood cells and proteins
During selective reabsorption, useful substances, including some water, are …
reabsorbed from the tubule back into the bloodstream.
During —————, useful substances, including some water, are reabsorbed from the tubule back into the bloodstream.
selective reabsorption
Useful substances, including some water, are reabsorbed from the tubule back into the bloodstream.
This leaves all …
urea, excess salts and excess water in the tubule.
During selective absorption, Useful substances, including some water, are reabsorbed from the tubule back into the bloodstream.
This leaves all urea, excess salts and excess water in the tubule.
This mixture forms urine, which is collected by—————- and travels to the bladder to be stored and then excreted.
the kidneys
During selective absorption, Useful substances, including some water, are reabsorbed from the tubule back into the bloodstream.
This leaves all urea, excess salts and excess water in the tubule.
This mixture forms ———-, which is collected by the kidneys and travels to the bladder to be stored and then excreted.
urine
During selective absorption, Useful substances, including some water, are reabsorbed from the tubule back into the bloodstream.
This leaves all urea, excess salts and excess water in the tubule.
This mixture forms urine, which is collected by the kidneys and travels to the ———- to be stored and then excreted.
bladder
Where does urine production take place?
Nephron
Name the two main stages in the process of urine production:
- Ultrafiltration
- Selective reabsorption
If there is too little water, the hypothalamus triggers the ————- to release anti-diuretic hormone (ADH).
pituitary gland
If there is too little water, the hypothalamus triggers the pituitary gland to release …
anti-diuretic hormone (ADH).
The hypothalamus triggers the pituitary gland to release anti-diuretic hormone (ADH).
This increases the …
permeability (ability of things to pass through) of the kidney tubules.
The hypothalamus triggers the pituitary gland to release anti-diuretic hormone (ADH).
This increases the permeability (ability of things to pass through) of the kidney tubules. This means that …
more water is reabsorbed back into the bloodstream.
The hypothalamus triggers the pituitary gland to release anti-diuretic hormone (ADH).
This increases the permeability (ability of things to pass through) of the kidney tubules. This means that more water is reabsorbed back into the bloodstream.
This results in …
a small volume of concentrated urine.
If there is too much water, The hypothalamus triggers the pituitary gland to stop the ——— of anti-diuretic hormone (ADH).
release
If there is too much water, The hypothalamus triggers the pituitary gland to stop the release of anti-diuretic hormone (ADH).
This —— the permeability of the kidney tubules.
reduces
If there is too much water, The hypothalamus triggers the pituitary gland to stop the release of anti-diuretic hormone (ADH).
This reduces the permeability of the kidney tubules. This means that …
less water is reabsorbed back into the bloodstream.
If there is too much water, The hypothalamus triggers the pituitary gland to stop the release of anti-diuretic hormone (ADH).
This reduces the permeability of the kidney tubules. This means that less water is reabsorbed back into the bloodstream.
This results in …
a large volume of dilute urine
Dialysis is one possible treatment for …
kidney failure.
The patient is linked up to the dialysis machine and their …
blood flows into the machine.
The dialysis machine contains a fluid that is designed to …
have the optimum concentrations of salts (e.g. sodium and potassium ions) and glucose, as would be found in a healthy person’s blood.
In dialysis machines, the patient’s blood passes over a —————- in the machine that is designed to replicate the kidney tubules.
partially permeable membrane
In dialysis machines, the patient’s blood passes over a partially permeable membrane in the machine that is designed to replicate the …
kidney tubules
The patient’s blood passes over a partially permeable membrane in the machine that is designed to replicate the kidney tubules.
The ————— is on the other side of the membrane.
dialysis fluid
The patient’s blood passes over a partially permeable membrane in the machine that is designed to replicate the kidney tubules.
The dialysis fluid is on the other side of the membrane. A concentration gradient is established, allowing …
excess ions and urea to diffuse from an area of high concentration in the patient’s blood to an area of low concentration in the dialysis fluid.
The patient’s blood flows into the dialysis machine, which contains a …
fluid (liquid or gas) that has the perfect concentration of salts and glucose.
The patient’s blood flows into the dialysis machine, which contains a fluid (liquid or gas) that has the perfect concentration of salts and glucose. Excess …
ions and urea diffuse out of the blood via diffusion.
What are the disadvantages of dialysis?
- Lasts 3-4 hours and is needed 3 times a week.
- Increases risk of blood clots and infections.
- Expensive process.
What are the advantages of dialysis?
- Dialysis is a life-saving process.
- It gives a patient more time to find a donor kidney.
Human beings are normally born with two kidneys but can survive with …
one kidney.
Many patients choose to have a kidney transplant, which often comes from a …
close relative.
Many patients choose to have a kidney transplant, which often comes from a close relative. Close relatives have a …
higher chance of being a tissue match.
Patients receiving a donor kidney often have to take …
immunosuppressant drugs for the rest of their lives.
Patients receiving a donor kidney often have to take immunosuppressant drugs for the rest of their lives.
These …
drugs suppress the immune system to prevent it from attempting to destroy the foreign cells of the transplanted kidney.
Kidneys can also be transplanted from ———————-, provided that they are a tissue match and have registered onto the organ donor register.
people who have recently died
What are the advantages of kidney transplants?
- The patient does not need to have dialysis treatment, which is time-consuming.
- Transplants are cheaper than dialysis in the long run.
What are the disadvantages of kidney transplants?
- The kidney may be rejected by the body.
- There can be long waiting lists for kidney transplants.
- The patient often has to take immunosuppressant drugs. - - These can make a patient more prone to other infections.
Features that appear during puberty are called …
secondary sex characteristics.
Males respond differently when their bodies reach puberty:
- The amount of the hormone testosterone rises. This stimulates sperm production.
- Underarm, facial and pubic hair grow.
- Voice deepens.
Females respond differently when their bodies reach puberty:
- The amount of the hormone oestrogen rises and triggers the menstrual cycle.
- Underarm and pubic hair grow.
- Breasts enlarge.
The menstrual cycle is a …
monthly cycle, which involves the maturation (process of maturing) and release of an egg.
The menstrual cycle is a monthly cycle, which involves the maturation (process of maturing) and release of an egg. If sexual intercourse has occurred, this can result in …
pregnancy
A female is born with all of her eggs ready, but only one egg will …
mature each month once the female reaches puberty.
The menstrual cycle is controlled by four hormones from the endocrine system:
- Follicle Stimulating Hormone (FSH)
- Oestrogen
- Luteinising Hormone (LH)
- Progesterone
The menstrual cycle can be divided into ——- stages depending on the levels of the hormones.
four
FSH stands for …
Follicle Stimulating Hormone.
FSH stands for Follicle Stimulating Hormone.
It is released by the pituitary gland and causes …
an egg in the ovary to mature.
FSH stands for Follicle Stimulating Hormone.
It is released by the ——— and causes an egg in the ovary to mature.
pituitary gland
FSH also stimulates (encourages) …
the production of oestrogen.
Oestrogen is produced in the ———- and causes the development of the thick, spongy uterus lining.
ovaries
Oestrogen is produced in the ovaries and causes …
the development of the thick, spongy uterus lining.
Oestrogen also stimulates the production of ————— and inhibits (stops) the production of FSH.
Luteinising Hormone (LH)
Oestrogen also stimulates the production of Luteinising Hormone (LH) and inhibits (stops) the production of …
FSH.
LH stands for …
Luteinising Hormone.
LH is produced by the ————- and stimulates the release of a mature egg on Day 14 of the menstrual cycle.
pituitary gland
LH is produced by the pituitary gland and stimulates the …
release of a mature egg on Day 14 of the menstrual cycle.
LH is produced by the pituitary gland and stimulates the release of a mature egg on Day 14 of the menstrual cycle.
This release is called …
ovulation
Progesterone is produced in the ————- after ovulation.
ovaries
Progesterone is produced in the ovaries after …
ovulation.
Progesterone is produced in the ovaries after ovulation.
It is responsible for …
maintaining the lining of the uterus during days 14-28.
When progesterone levels drop, this triggers …
the breakdown of the lining.
When progesterone levels drop, this triggers the breakdown of the lining. This marks …
day 1 of the next menstrual cycle.
Progesterone also inhibits (stops) …
the release of LH and FSH.
Stage 1of the menstrual cycle (days 1-4):
The uterus lining breaks down, resulting in a ‘period’.
Stage 2 of the menstrual cycle (days 4-14):
The uterus lining starts to build up again into a thick, spongy layer full of blood vessels.
Stage 3 of the menstrual cycle (day 14):
Ovulation happens. This is when an egg is released from one of the ovaries.
Stage 4 of the menstrual cycle (day 15-28):
The uterus lining is maintained, which means that it is now ready for the arrival of a fertilised egg (which will eventually grow into a baby). If no fertilised egg is attached to the uterus lining, the lining breaks down and the cycle begins again.
How many stages are there of the menstrual cycle?
4
The contraceptive pill comes in two main forms:
- Progesterone-only pill
- Combined pill
The Progesterone-only pill stimulates the production of ——————, which is very difficult for any sperm to penetrate.
thick, sticky mucus
The Progesterone-only pill stimulates the production of thick, sticky mucus, which is …
very difficult for any sperm to penetrate.
Progesterone-only pill inhibits the release of …
FSH, so that eggs don’t mature.
The progesterone-only pill is just as effective as …
the combined pill but with fewer side effects.
Combined pill contains both …
oestrogen and progesterone
By taking the combined pill every day, enough ———— builds up in the female body to inhibit the production of FSH so that no eggs mature.
oestrogen
By taking the combined pill every day, enough oestrogen builds up in the female body to inhibit the …
production of FSH so that no eggs mature.
How often is the combined contraceptive pill taken?
Daily
Research and developments in technology have led to more contraceptive methods. These contraceptives don’t have to be taken daily:
- Contraceptive injection
- Contraceptive implant
- Contraceptive patch
The contraceptive injection contains ————— and can last up to three months.
progesterone
The contraceptive injection contains progesterone and can last up to …
three months.
The contraceptive implant, which can last for —————, is inserted under the skin (normally in an arm) and continuously releases a small amount of progesterone.
3 years
The contraceptive implant, which can last for 3 years, is inserted —————— and continuously releases a small amount of progesterone.
under the skin (normally in an arm)
The contraceptive implant, which can last for 3 years, is inserted under the skin (normally in an arm) and continuously releases a …
small amount of progesterone.
The woman places the small contraceptive patch onto the ——, which only has to be changed once a week.
skin
The woman places the small contraceptive patch onto the skin, which only has to be changed once a …
week
The woman places the small contraceptive patch onto the skin, which only has to be changed once a week.
This steadily releases …
progesterone
Which hormone is released by the contraceptive patch, injection and implants?
Progesterone
Some contraceptive methods work by being inserted into the woman’s body:
- Intrauterine devices (IUDs)
- Diaphragms
Intrauterine devices (IUDs)
is also known as …
the coil
Intrauterine devices (IUDs) are …
small t-shaped devices that are inserted into the uterus.
Intrauterine devices (IUDs) work by …
preventing implantation of an embryo (fertilised egg).
Some intrauterine devices also release …
progesterone
A diaphragm is a —————, which is inserted into the vagina prior to sexual intercourse and sits at the entrance to the uterus.
shallow plastic cup
A diaphragm is a shallow plastic cup, which is inserted into the ———- prior to sexual intercourse and sits at the entrance to the uterus.
vagina
A diaphragm is a shallow plastic cup, which is inserted into the vagina prior to …
sexual intercourse and sits at the entrance to the uterus.
A diaphragm is designed to …
prevent the sperm from reaching the egg.
A diaphragm can also be covered in a …
spermicide to kill the sperm.
Condoms are effective in protecting against …
sexually transmitted infections (STIs), such as chlamydia, gonorrhoea and HIV.
Condoms can be worn by the male on …
his penis during sexual intercourse
Condoms often contain a —————, which kills the sperm on release.
spermicide
Condoms prevent the sperm from …
entering the female during ejaculation
Condoms prevent the sperm from …
entering the female during ejaculation
For a man, sterilisation involves having …
the sperm ducts (the tubes between the testes and the penis) cut so that the sperm are not released on ejaculation.
For a woman, sterilisation involves having …
the fallopian tubes (ducts which connect the ovaries to the uterus) cut so that an egg cannot reach the uterus.
Since a female’s body temperature usually ——— during ovulation, some women choose to avoid sexual intercourse on days when they know (or feel) that they are ovulating.
rises
Since a female’s body temperature usually rises during ovulation, some women choose to avoid sexual intercourse on days when they know (or feel) that they are ovulating.
However, sperm can last up to ——— inside the woman’s body, so this is not a very reliable or effective method of contraception.
six days
The only truly effective way (apart from sterilisation) to avoid pregnancy is …
abstinence
The only truly effective way (apart from sterilisation) to avoid pregnancy is abstinence.
This simply means that a …
couple chooses to not have sexual intercourse unless they are ready for a baby.
Some women don’t have high enough levels of ——- to stimulate the maturation of their eggs.
FSH
Modern reproductive technologies can help these women to give birth:
- Fertility drugs
- In-vitro fertilisation (IVF)
A Fertility drug that contains a mixture of ———— can be prescribed by a doctor.
FSH and LH
Boosting the levels of ————— can cause an egg to be released in the ovaries.
FSH and LH
———— are given to stimulate the growth of lots of eggs.
FSH & LH
In —————-, FSH & LH are given to stimulate the growth of lots of eggs.
Eggs are collected before being fertilised in a petri dish in a laboratory, using sperm from the father.
These fertilised eggs grow into embryos and are implanted into the woman’s uterus.
In-vitro fertilisation (IVF)
In In-vitro fertilisation (IVF), Eggs are collected before …
being fertilised in a petri dish in a laboratory, using sperm from the father.
In In-vitro fertilisation (IVF), These fertilised eggs grow into …
embryos and are implanted into the woman’s uterus.
These eggs are then collected before being fertilised in a dish in a laboratory, using sperm from the father.
This is why babies born using this technique are often called ‘—————-’.
test tube babies
Why is more than one embryo usually implanted in an IVF treatment?
Sometimes two embryos might be implanted to try to increase the probability of pregnancy.
The advantage of fertility treatments is that they offer fresh hope to couples who are unable to conceive naturally. However, they also have disadvantages:
- Multiple pregnancies
- Stress
- Expensive
Fertility treatments are not …
guaranteed to work and can be very expensive.
Fertility treatments rates are …
not that high and many attempts may be needed.
In an IVF treatment, eggs are collected from the mother and taken to a dish in a ————- to be fertilised using sperm from the father.
laboratory
An infertile woman has insufficient levels (doesn’t have enough) of which hormone?
FSH
Which word means ‘resting’ when discussing metabolic rates?
Basal
The key plant hormones are:
- Gibberellins
- Auxins
- Ethene
Auxins change growth patterns to allow …
roots and shoots to move either towards or away from a stimulus (change in conditions).
Responses to stimuli that involve directional growth are called …
tropisms
————- are important in starting off the seed germination (sprouting) process.
Gibberellins
Gibberellins are important in …
starting off the seed germination (sprouting) process.
Ethene is a gas that …
controls cell division and the ripening of fruits.
Tropisms are controlled by …
auxins
Tropisms are controlled by auxins. They are groups of responses that can be split into:
- Phototropisms
- Gravitropisms (or geotropisms)
Growth either ———————- the direction of gravity.
towards (positively gravitropic) or away from (negatively geotropic)
Phototropisms involve …
growth either towards (positively phototropic) or away from (negatively phototropic) a light source.
What is a negative gravitropism?
A plant growing away
from the direction of
gravity
1 side of the shoot is exposed to more light.
Auxin is redistributed within the shoot so that …
the concentration is greater on the shaded side.
1 side of the shoot is exposed to more light.
Auxin is redistributed within the shoot so that the concentration is greater on the shaded side.
This unequal auxin distribution will result in …
increased cell elongation (grows longer) on the shaded side.
In shoots, auxins promote the …
elongation of cells.
In shoots, auxins promote the elongation of cells.
However, in roots, auxins prevent …
the elongation of cells.
A positive phototropism describes …
a plant growing towards a light source.
Words ending in tropism are …
responses to stimuli that involve directional growth.
Auxins have different functions in different locations within the plant. What are they?
- In roots, auxins prevent elongation of cells.
- In shoots, auxins promote elongation of cells.
The effect of light on seedlings can be demonstrated with mustard or cress seeds. Complete the following steps:
- Place the seeds in petri dishes with damp cotton wool, and leave them in a warm place to germinate (develop).
- Randomly divide the Petri dishes into three groups and assign each group to one of the following light conditions:
Full sunlight in a windowsill
Darkness
Partial light - Measure the height of each plant every day for a week.
- Draw and label biological drawings to show the effects.
- The independent variable is the lighting conditions.
The dependent variable is the growth of the plant. - Phototropism can also be demonstrated by placing a seedling in a container that is open only on one side.
To investigate the effect of light and gravity on plant growth, which three conditions should we place the plants in?
- full sunlight
- partial sunlight
- full sunlight
Auxins are used as …
weed killers as they can initiate (start) such rapid growth that the weeds use up all of their resources and die.
Auxins are also used as …
rooting powders (growth supplement) and to promote growth in tissue culture.
Gibberellins are used to …
promote flowering, increase fruit size, and initiate (start) seed germination.
Ethene is used in …
the food industry to control the ripening of fruit during storage and transport.
