Homeostasis Flashcards
What makes up the central nervous system
Brain 🧠
Spinal cord 🦴
Order of reactions
Stimulus
Receptor
Coordinator
Effector
Response
Order of a reflex reaction
Stimulus
Receptor
Sensory neuron
Relay neuron
Motor neuron
Effector
Response
What is reaction time
The time taken to react to a stimulus
What can reaction time be affected by
Alcohol
Drugs
Fatigue
Distraction
Age
Sex
Stimulus type
What do receptors detect
Changes in the environment (stimuli)
Neurons transmit…from receptors to CNS
…electrical impulse…
What does the CNS do
Coordinates a response
What do effectors do
Bring about a response (muscles/glands)
Reflex actions
A fast and automatic response. Often stop us from getting hurt
The relay neuron is either in the unconscious brain 🧠 or spinal cord 🦴
What is a synapse
A gap between 2 neurons
What happens when an electrical impulse gets to a synapse
Triggers the release of a chemical messenger which diffuses across the gap and binds to the neurons. This then triggers a new electrical impulse.
What is homeostasis
The regulation of the conditions inside your body to maintain a stable internal environment, in response to changes in internal and external conditions.
What conditions are regulated inside the body
Temperature
Blood sugar/glucose levels
Blood water content
What is the endocrine system
A series of glands around the body
What are glands
Specialised organs that produce hormones to react to a change in the body’s environment
What are hormones
Chemical messengers which travel in the blood to activate target organs
What does the pituitary gland (master gland) do
Produces hormones that regulate body conditions and stimulates other glands to produce different hormones
What does the thyroid gland do
Regulates basal metabolic rate and stimulates growth and development
Thyroxine
What does the adrenal gland do
Prepares the body for “fight 🥊 or fight ✈️” responses by increasing delivery of oxygen and glucose to brain and muscles
Adrenaline
What does the pancreas gland do
Helps to lower/increase blood glucose levels
Insulin/glucagon
What do the ovary glands do
Control the menstrual cycle
Oestrogen
What do the testes glands do
Control puberty and sperm production
Testosterone
How do you test for diabetes
Urine tested with Benedict’s regent
If inconclusive a blood test is more reliable since it’s accurate to the time and glucose concentration
What causes type 1 diabetes
Pancreas fails to produce enough insulin
What causes type 2 diabetes
Body cells no longer respond to insulin
What age are you more likely to have type 1 diabetes
Early age
What age are you more likely to get type 2 diabetes
Later in life
Symptoms of diabetes
Weight loss
Exhaustion
Constant urination
Treatments for type 1 diabetes
Insulin injections
Treatments of type 2 diabetes
Carb controlled diet
Exercise
Risk factors for type 1 diabetes
Genetic
Risk factors for type 2 diabetes
Lifestyle
High glucose levels
Receptors in the pancreas detect the high blood levels
The pancreases secretes insulin into then blood
Cells in the muscles and liver detect the insulin
They take glucose out of the blood and store it as glycogen
Low glucose levels
Receptors in the pancreas detect low glucose levels
The pancreas secretes glucagon
Cells in the muscles and liver detect the glucagon
They convert the glycogen inside their cells into glucose and release it into the blood
What would happen if glucose levels got too high
Water could move out of the blood cells due to osmosis
What would happen if glucose levels got too low
There wouldn’t be enough for sufficient respiration
First step in the menstrual cycle
Days 1-4
Menstruation - uterus lining breaks down
Second step in the menstrual cycle
Days 4-14
Uterus lining builds back up to receive a fertilised egg
Third step in the menstrual cycle
Day 14
Ovulation - egg released from ovaries
Forth step in the menstrual cycle
Uterus lining maintained, if no fertilised egg is implanted, the lining breaks down again
FSH
Produced in the pituitary gland
Matures egg
Stimulates production of oestrogen
Oestrogen
Produced in the ovaries
Inhibits production of FSH
Builds up uterus lining
Stimulates production of LH
LH
Produced in the pituitary gland
Stimulates ovulation
Stimulates production of progesterone
Progesterone
Produced in the ovaries (follicle)
Inhibits the production of LH and FSH
Maintains uterus lining
Steps of IVF
- The woman is given FSH and LH to stimulate egg
maturation and release - Eggs are harvested from the ovaries
- Sperm are collected from the man
- Eggs and sperm are mixed to allow fertilisation
- An embryo is developed in the lab
- Embryos are implanted back into the uterus
Advantages of IVF
Couples can be helped to conceive
Can genetically screen the embryo to check for genetic disorders
Disadvantages of IVF
Ethically questionable for unused embryos to be destroyed
Increased pregnancies (twins/triplets) which causes more danger to the mother and babies
Expensive
40% chance for working
Stressful
What is an ectopic pregnancy
Where the foetus develops outside the uterus e.g. the fallopian tube’s
What is a negative feedback loop
Responds when internal conditions change from the ideal point and returns the conditions to normal
What dues thyroxine control
The speed oxygen and food products react to release energy
What does adrenaline do
Increased heart rate
Increases breathing rate
Increased delivery for oxygen and glucose to brain 🧠 and muscles 💪 for increased respiration
Diverts blood away from areas, such as the digestive system, towards the muscles
( not a negative feedback )
