Unit 2 : Multi-cellular Organisms - Control and Communication Flashcards
What does our nervous system control ?
Our nervous system controls every action that we make.
What does our nervous system consist of ?
Central Nervous System / Peripheral Nervous System
What does the central nervous consist of ?
Brain & spinal cord
What is the flow of information ?
receptors (sensory organs) -[sensory nerves]- CNS - [motor nerves]- effectors (muscle/glands)
What are the 3 main parts of the brain ?
Cerebrum, Cerebellum & Medulla
What is the function of the cerebrum ?
Largest part of the brain. Responsible for mental processes such as memory, reasoning, imagination, conscious thought and intelligence.
What is the function of the cerebellum ?
Controls balance & co-ordination. Sorts out information from the semi-circular canal.
What is the function of the medulla ?
Controls the rate of breathing and heart beat.
What are nerve cells in the nervous system called ?
neurons.
What does a neuron have ?
cell body & nerve fibres.
What are fatty sheath around axons for ?
insulation and to speed up nerve impulses.
What is the gap between neurons called ?
synapse
How are electrical impulses generated in the next neuron ?
Chemical transmitter substances are released from tiny vacuoles at the end of one neuron that diffuse across the synapse.
What are the 3 types of neurons ?
Sensory neuron, relay neuron & motor neuron
What is the function of a sensory neuron ?
Carry information from a sensory organ/ receptor to the CNS.
What is the function of the relay neuron ?
Carry information from the nerve cell to nerve cell in the CNS.
What is the function of the motor neuron ?
Carry information from the CNS to a muscle or to a gland. (effector organs)
Describe the response from a muscle ?
Rapid action
Describe the response of a gland ?
slower response
What is a reflex action ?
A reflex action is a rapid automatic response to a
stimulus.
What are reflex actions for ?
Reflex actions help to protect the body from damage.
What is name given to the nervous pathway for such reflexes ?
reflex arc
Describe the reflex action for touching a hot object ?
The stimulus is detected by temperature receptors in the skin. This triggers a nerve impulse in the sensory neuron. The nerve impulse travels in the sensory neuron to the spinal cord. The sensory neuron enters the spinal cord. The sensory neuron connects by a synapse to a relay neuron, which in turn connects to the motor neuron. The impulse travels along the motor neuron out of the spinal cord to the effector organ (bicep muscle). The muscle responds by contracting and causing the arm to move.
Describe the knee jerk reflex ?
Stimulus is detected by receptors. Signal travels along sensory neutron. Signal passes from the sensory neuron to the relay neuron. Signal passes from relay neuron to motor neuron. Signal reaches muscle. Muscle responds.
What are hormones ?
chemical messengers
Where are hormones produced ?
Hormones are produced in endocrine glands.
How do hormones travel around the body ?
They travel in the bloodstream to their target tissue
Name the hormone and target tissue produced from the adrenal gland ?
Adrenaline / heart
Name the hormone and target tissue produced from the pancreas ?
Insulin & glucagon / liver
Name the hormone and target tissue produced from the ovaries ?
Oestrogen / uterus
Name the hormone and target tissue produced from the testes ?
Testosterone / muscles
Name the hormone and target tissue produced from the thyroid gland ?
Thyroxine / most cells
Name the hormone and target tissue produced from the pituitary gland ?
growth hormone / most cells
What are the comparisons between the nervous and endocrine system ?
Nervous system relies on impulses whereas the endocrine system relies on chemical messengers. Nervous system is quick acting whereas the endocrine system is slow acting. Nervous systems is a short term response whereas the endocrine system is a longer response.
What 2 hormones are blood glucose levels controlled ?
Insulin / glucagon
Describe glucose levels immediately after a meal ?
1) High blood sugar level is picked up by the pancreas.
2) Pancreas produces insulin.
3) Insulin travels in the bloodstream to the liver.
4) Insulin promotes the conversion of glucose into glycogen.
5) The blood sugar level is lowered.
Describe glucose levels after exercise ?
- Low blood sugar is picked up by the pancreas.
- Pancreas produces glucagon.
- Glucagon travels in the bloodstream to the liver.
- Glucagon promotes the breakdown of glycogen into glucose.
- The blood sugar level increases.
What 2 ways can we test for a diabetic?
- A clinistix test on urine. (When pink changes to purple, glucose is present)
- Glucose tolerance curve
How do we produce a glucose tolerance curve ?
The patient is given a glucose drink of known volume.
The blood glucose level is then monitored over 3 hours.
What would we expect to see to the blood glucose level of the diabetic individual just as the glucose drink was given in comparison to the non-diabetic individual ?
The blood glucose level at the start is higher for the diabetic individual.
What would we expect to see to the blood glucose level of the diabetic individual after about an 1 hour of having the glucose drink in comparison to the non-diabetic individual ?
When the glucose drink was given to the diabetic individual the blood glucose level rises to a much higher level and after an hour of have the drink still no insulin has been produced whereas the non-diabetics blood glucose level is beginning to return to its normal state.
What would we expect to see to the blood glucose level after 2 hours of having the drink in comparison to the non-diabetic individual ?
After about 2 hours the diabetics blood glucose level begin to decrease as glucose is lost in the urine. The non-diabetic individual is just about back to its normal state.
What would you expect to see to the blood glucose level of the diabetic individual after 3 hours after having the drink in comparison to the non-diabetic individual ?
The diabetics blood glucose level has still not returned to its original state and the non-diabetic individual glucose level has returned to its normal state.
What is the cause of type 1 diabetes ?
The body is unable to produce any insulin and glucose builds up in the blood.
What age does type 1 diabetes usually occur at ?
young age
What treatment is given to type 1 diabetics ?
Daily insulin injections, healthy diet and regular exercise.
What is the cause of type 2 diabetes?
Cells become resistant to insulin.
What age does type 2 diabetes usually occur at ?
Later in life - older
What is usually associated with type 2 diabetes ?
obesity
What treatment is given to type 2 diabetics ?
healthy diets and regular exercise
