A2 Nervous System Flashcards
What are the 3 things that make up the central nervous system?
Nerves, Brain and Spinal Cord
What is the role of the nervous system?
It is responsible for coordinating responses
What is the nervous system comprised of?
The central nervous system and the peripheral nervous system. The peripheral consists of motor and sensory. The motor system is composed of autonomic and somatic and the autonomic is composed of sympathetic and parasympathetic.
What are neurons and what are they made up of?
Cell body, dendrites, nucleus, myelinated sheath, node of ranvier, axon, schwann cell
What is resting potential?
The nerve not being stimulated
What is the role of the sodium-potassium pump in maintaining resting potential?
A transport protein that pumps potassium ions into the cell while simultaneously pumping sodium ions out of the cell
Describe what happens during resting potential
This happens in the cell membrane of the neuron.
1) Soduim and potasdsium channels are closed
2) The NA/K pumps 3 NA ions out of the axon and 2 K inside the axon 3) As result the resting potential is -70mv because more
Describe what happens during action potential
1) Stimulus triggers NA channels open 2) NA ions move into axon if a threshold is reached then more NA channels open causing depolarisation 4) When 40 mv is reached NA channels close and K ion channels open causing repolarisation
What happens during synaptic transmission?
1) AP (action potential) arrives at the end of presynaptic response
2) Calcium channel opens
3) Vesicles with neurotransmitters fuse with the membrane of presynaptic neurone 4) Releasing neurotransmitters into synaptic cleft 5) Neurotransmitters binds to receptor on the postsynaptic neurone 6) This causes NA channels to open 7) New AP is triggered
What is the hyopthalamus gland and where is it located?
It is located in the brain and involved in thermoregulation
What happens during vasoconstriction?
The muscles in the arteriole walls contract causing the arterioles near the skin to constrict and allowing less blood to flow through skin capillaries.
Blood is directed away from the capillaries close to the skin.
Shunt vessels dilate.
Blood passes through shunt vessels rather than skin capillaries.
Less heat is lost by radiation.
Blood is directed to the internal organs to maintain core body temperature.
What happens during vasodilation?
Blood is directed towards the capillaries close to the skin.
Shunt vessels constrict.
Less blood passes through the shunt vessels and is forced through the skin capillaries.
More heat is loss by radiation.
What is hypothermia?
A process occurs when your body loses heat faster than it can generate heat, causing a low body temperature. It occurs when your body temperature falls below 35c
Your heart, nervous system and organs cannot function properly and can lead to failure of your heart and respiratory system and can lead to death.
Symptoms include shivering, pale, cold and dry skin, slurred speech, low breathing.
What is thermoregulation?
The control of internal body temperature
What is homeostasis?
Mechanisms to maintain dynamic equilibrium, with small fluctuations over a narrow range of conditions despite changes in the external or internal conditions. Some things that must be kept constant are temperature, pH, water levels and blood pressure.
