Response and Regulation 2 Flashcards
What is the endocrine system?
A system that sends messages around the body through hormones
How does information travel in the endocrine system?
In form of hormones + In the blood + Slowly
What is the difference between the effects brought along by the nervous system and endocrine system?
Electrical impulse effects end quickly while hormones have a lasting effect
Where are hormones produced?
Organs called endocrine glands
What are glands?
Specialised organs that release hormones. They have a dense network of blood capillaries to secrete hormones into.
What are examples of endocrine glands?
Pituitary gland, thyroid, and adrenal gland
Where is the pituitary gland located?
At the base of the brain
Which hormone does the adrenal gland produce and what function does it serve?
Adrenaline
Prepares the body for activities that need energy and quick reflex actions (fight or flight)
Which hormones does the pancreas produce and what function do they serve?
Insulin
Makes liver reduce blood glucose level
Glucagon
Makes liver increase blood glucose level
Which hormone do the testis produce and what function does it serve?
Testosterone
Produces male secondary sexual characteristics
Which hormones do the ovaries produce and what function do they serve?
Oestrogen
Produces female secondary sexual characteristics
Progesterone
Helps control menstrual cycle and maintain pregnancy
What is homeostasis and why is it important?
The regulation of our body’s internal conditions in response to a change in environment to ensure our enzymes and cells function well. Otherwise, they could denature.
Which conditions inside of our body need to be regulated?
Carbon dioxide levels Blood sugar (glucose) levels Urea concentration in urine Internal body temperature Water levels
What is negative feedback?
When an internal condition changes to be no longer optimal and the body works to counteract (reverse) the change and return conditions to the optimum.
What does the negative feedback loop involve?
- Internal condition changes
- Change detected
- Corrective mechanisms activated
- Conditions return to normal
- Corrective mechanisms deactivated
What are the side-effects of having too much glucose?
If blood glucose levels are too high, this can have a negative impact on osmosis (movement of water between cells) by affecting concentration gradients
What are the side-effects of having not enough glucose?
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.
How will the body try to bring glucose levels back to normal (in general)?
The negative feedback loop
What is glycogen?
An insoluble form of glucose that can be stored for later
What is glucagon?
A hormone formed in the pancreas which promotes the breakdown of glycogen to glucose in the liver
What happens when blood glucose is too low?
Glucagon is released from the pancreas which stimulates the liver to convert stored glycogen to glucose and release it into the blood
What happens when blood glucose is too high?
Insulin is released from the pancreas which stimulates the liver to take in excess glucose which is stored as glycogen
What vital life process is glucose required for?
Respiration
When would someone’s blood glucose levels increase?
When a person eats food containing glucose
When would someone’s blood glucose levels decrease?
When glucose is used up in respiration e.g. exercise
What is type 1 diabetes?
When the pancreas cells are unable to produce enough insulin, meaning glucose is not being reduced
Blood sugar is TOO HIGH
How can type 1 diabetes be treated?
Injecting insulin when blood glucose levels rise too high + managing diet and exercising properly
What is type 2 diabetes?
When insulin is still produced, but the body no longer responds to it
Blood sugar is TOO HIGH
How can type 2 diabetes be treated?
Insulin injections do not help because the body no longer responds to it.
Diet and exercise must be regulated
What are the symptoms/side effects of diabetes?
Weight loss Urination Increased thirst Tiredness Blurry vision Wounds take longer to heal Thrush
How would you test a urine sample for glucose?
Add equal volumes of Benedict’s reagent and the urine sample to a boiling tube and heat in a hot water bath. If a red precipitate is formed, glucose is present.
OR
using reagent test strips which are dipped into urine and change colour to indicate the concentration of glucose present
What is the control of body temperature called?
Thermoregulation
What could happen if our body temperature becomes too high?
The enzymes that control the chemical reactions in oour body that keep us alive could denature
How does our body monitor temperature?
Receptors on the surface of the skin track our external body temperature
Receptors in the hypothalamus in the brain monitor our internal body temperature as blood flows through the brain
What are the three sections of the sweat producing body part called and what do they do?
Sweat gland - Produces sweat
Sweat duct - Tube that sweat travels through
Sweat pore - Where sweat leaves the skin
How does our body respond to temperature being too low?
Blood vessels constrict (vasoconstriction)
Hairs stand on end
Shivering (muscle contractions)
How does our body respond to temperature being too high?
Blood vessels get wider (vasodilation)
Sweat produced
Hairs remain close to skin
What effect do blood vessels have on our body temperature?
When they are wider the blood flows nearer to the surface of the skin so heat can be lost by radiation. The opposite applies to when they constrict
What effect do hairs standing on end have on our body temperature?
When they are raised they trap a layer of air close to the skin which insulates the skin. Even when they lie flat they still trap a layer of air, but it is thinner.
What are the effectors involved in thermoregulation?
Muscles
Sweat glands
Hair erector muscles
Blood capillaries
How does shivering help us warm up?
The muscle movement requires energy generated through respiration. Respiration produces heat which warms us up
How does sweating help us lose body heat?
Heat energy from the body is transferred to the layer of water which evaporates, taking the heat with it
What are the types of phototropisms?
Positive phototropism: Growing towards a light source
Negative phototropism: Growing away from a light source
What are the types of gravitropisms?
Positive gravitropism: Growth towards the direction of gravity
Negative gravitropism: Growth away from the direction of gravity
What is the purpose of the tropisms?
To ensure a plant will grow the right way up whatever direction their seed lies in the soil. They also ensure the shoots can grow towards the light for photosynthesis
What are plant responses to stimuli brought about by?
Hormones called auxins.
The concentration of the auxin on the side of the plant that is not receiving stimulus increases so growth occurs in the direction of the stimulus (cells elongate where auxins are present)
Where in a plant are auxins produced?
The tip
In what situations can a plant not produce auxins?
When the tip has been removed
When the tip is obscured and so cannot receive light
When the tip is separated from the rest of the plant by something auxins cannot diffuse across
What are the functions of auxins in different locations in a plant?
In roots, auxins prevent elongation of cells.
In shoots, auxins promote elongation of cells.
