Unit 1 Part 2: organ systems, Immunity and genetics Flashcards
organ systems, immunity and genetics (28 cards)
what is the nervous system made up of?
nerve cells called neurons.
what is a nerve impulse?
The electrical signals transmitted throughout the nervous system.
in the structure of a neuron, explain the role of an axon.
A long nerve fibre of a neuron which carries a nerve impulse.
in the structure of a neuron, explain the role of dendrites.
slender extensions from the cell body which connect with neighbouring neurons.
in the structure of a neuron, explain the role of schwann cells.
specialised cells associated with the axons of the myelinated neurones, forms the insulating ,myelin sheath.
in the structure of a neuron, explain the role of the myelin sheath.
fatty insulating layer around some axons produced by the schwann cells.
in the structure of a neuron, explain the role of the node of ranvier.
gaps between the schwann cells that enable saltatory conduction. This speeds up nerve impulses.
what is the name of the direction of nerve impulse along a neuron that travels towards the cell body?
dendrites
what is the name of the direction of nerve impulse along a neuron that travels away from the cell body?
axons
what is the (CNS)?
the (CNS) is the central nervous system linking the brain and spinal chord that coordinate a response to a stimulus. This only involves relay neurons.
what is the (PNS)?
the (PNS) is the peripheral nervous system that involves all of the nerves outside the brain and spinal chord. This involves only sensory neurons and motor neurons.
what are reflex reactions?
involuntary actions that involve sensory, relay and motor neurons however the brain is not initially involved.
Villi surround the small intestine so give me 3 adaptations of the villi that help make digestion more efficient?
The capillary network increases blood supply. Large surface area which increases the uptake of nutrients. Thin walls therefore a shorter distance for the molecules to travel into the blood.
Explain how carbohydrate assimilation occurs?
At the liver glucose is stored as glycogen, this glycogen rapidly hydrolyses to provide glucose for respiration and the excess is converted into triglycerides and stored in the fat tissue under the skin.
What does a nerve conduction test consist of?
Test how fast impulses move through neuron’s.
Explain the effects of myelination on neurons on how it affects its transmission speeds?
The transmission of the action potential is much faster when myelinated as it insulates the neuron.
What is saltatoty conduction?
Where the action potential or nerve impulses jumps from one node of ranvier to another.
What is a synapse?
The small gap between two neurones and neurotransmitters carry the message across the synapse.
What is the structure like in the presynaptic neurone?
Lots of mitochondria which provides energy in the form of ATP.
What do the neurotransmitters bind to and what do they cause when there is enough of them?
Neurotransmitters bind to the receptors in the postsynaptic neurone which triggers sodium ion chemicals to open when there are enough neurotransmitters present.
What are all the parts of the digestive system?
Liver, stomach, pancreas, gallbladder, duodenum, ileum, colon, rectum, appendix and caecum.
What is the function of the stomach?
Churn food to digest it and contains HCL to kill of any bacteria ingested.
What is the function of the pancreas?
Contains both exocrine and endocrine glands for digestion and hormones.
