The Nervous System Flashcards
Explain the 2 main structural systems that the nervous system is split into
1) Central Nervous System = made up of the brain and spinal cord
2) The peripheral nervous systems =this has 2 different functional systems
-the somatic nervous system = controls conscious, voluntary activities e.g running
-the autonomic nervous system = controls unconscious, involuntary activities e.g digestion =this has 2 divisions which have opposite effects on the body
-the sympathetic nervous system= gets the body ready for action, fight or flight, neurones release noradrenaline
-the parasympathetic nervous system= calms the body down, rest and digest, neurones release acetylcholine
Outline the similarities and differences between the autonomic nervous system and the somatic nervous system
Similarities:
-in somatic NS neurotransmitter at the effector is Acetylcholine
-in parasympathetic NS of Autonomic NS, neurotransmitter at the effector is Acetylcholine
-both systems can have a stimulatory effect
Differences:
-autonomic NS can also have inhibitory effect depending on neurotransmitter
-autonomic NS have both lightly myelinated and unmyelinated axon, whereas somatic NS has heavily myelinated axon
-the autonomic NS effector organs are smooth muscle, glands, cardiac muscle, whereas somatic NS effector organs are skeletal muscle
In the autonomic nervous system, what effect does each system have on
-heart rate
-breathing rate
-pupils
-sweat glands
-heart rate = parasympathetic slows down, sympathetic speeds up
-breathing rate = parasympathetic slows down (constrict bronchioles), sympathetic speeds up
-pupils= parasympathetic pupils constrict, sympathetic pupils dilate
-sweat glands= parasympathetic increases sweat made (decreasing internal body temperature)
Label this structure of the brain
1) hypothalamus
2) pituitary gland
3) medulla oblongata
4) cerebellum
5) cerebrum
Explain the function of the brain part cerebrum
-involved in vision, hearing, learning and thinking
-conscious thought
-higher brain function
-memory
Explain the function of the brain part hypothalamus
-automatically maintains body temperature at the normal level
-produces hormones that control the pituitary gland
Explain the function of the brain part pituitary gland
-releases hormones
-stimulates other glands e.g adrenal gland to release their hormones
Explain the function of the brain part medulla oblongata
-automatically controls breathing rate and heart rate
Explain the function of the brain part cerebellum
-muscle coordination
-posture
-coordination of balance
What is the fight or flight response?
-when an organism is threatened it responds by preparing the body for action (for fighting or for running away)
Explain how both the nervous and hormonal systems coordinate the fight or flight response
-nerve impulses from sensory neurones arrive at the hypothalamus activating both the hormonal system and the sympathetic nervous system
-the pituitary gland is stimulated to release a hormone called ACTH. This causes the cortex of the adrenal gland to release steroidal hormones
-the sympathetic nervous system is activated, triggering the release of adrenaline from the medulla region of the adrenal gland
Explain the effects that the sympathetic nervous system and adrenaline have in the fight or flight response
-heart rate is increased = so blood is pumped around the body faster
-the muscles around the bronchioles relax = so breathing is deeper
-glycogen is converted into glucose = more glucose is available for muscles to respire
-muscles in the arterioles supplying the skin and gut constrict, and muscles in the arterioles supplying the heart, lungs and skeletal muscles dilate = so blood is diverted from the skin and gut to the heart, lungs and skeletal muscles
-erector pili muscles in skin contract = this makes hairs stand on end so animal looks bigger
Explain how the nervous system helps to controls heart rate
NERVOUS SYSTEM:
1) The sinoatrial node (SAN) generates electrical impulses that cause the cardiac muscle to contract
2) the rate at which ghe SAN fires is unconsciously controlled by a part of the brain called the medulla
3) animals need to alter their heart rate to respond to internal stimuli e.g to prevent fainting due to low blood pressure or make sure heart rate is high enough to supply the body with enough oxygen
4) stimuli are detected by pressure receptors and chemical receptors. Pressure receptors (baroreceptors) in the aorta and vena cava, stimulated by high and low blood pressure. Chemical receptors (chemoreceptors) in the aorta, the carotid artery and the medulla. They monitor the oxygen level in the blood and co2 and pH
5) electrical impulses from receptors are sent to the medulla along sensory neurones. The medulla processes the information and sends impulses to the SAN along motor neurones
For each different stimulus give the receptor, the neurone, the effector and the response:
-high blood pressure and high blood oxygen
-low blood pressure and low blood oxygen
HIGH BLOOD PRESSURE:
-receptor = baroreceptors for pressure // chemoreceptors for chemical change in blood
-neurone = impulses sent to medulla, which send along vagus nerve, secreting acetylcholine, which binds to receptors on SAN
-effector = cardiac muscles
-response = heart rate slows down to reduce blood pressure back to normal, and return of o2, co2 and pH back to normal
LOW BLOOD PRESSURE
-receptor = baroreceptors // chemoreceptors for chemical changes in blood
-neurone = impulses sent to medulla, sent along accelerator nerve, secreting noradrenaline, binds to receptors on SAN
-effector = cardiac muscle
-response = heart rate speeds up to increase blood pressure back to normal, return of o2, co2 and pH back to normal
How does the hormonal system help to control heart rate?
-it releases adrenaline (when fight or flight response is activated)
-adrenaline binds to specific receptors in the heart. This causes the cardiac muscle to contract more frequently and with more force, so heart rate increases and the heart pumps more blood
