Chapter 13- Neuronal communication Flashcards
What is homeostasis?
Homeostasis is the maintenance of a stable equilibrium in the conditions inside the body
What is a stimulus?
A stimulus is a detectable change in the external or internal environment of an organism.
What is a neurone?
A neurone is specialised nerve cell which transmits electrical impulses rapidly in the form of action potentials.These are the bodies response to stimuli.
What does the cell body contain?
The cell body contains the nucleus surrounded by the cytoplasm.There are also large amounts of endoplasmic reticulum and mitochondria which are involved in the production of neurotransmitters.
What are dendrons?
These are short extensions which come from the cell body. These extensions divide further into smaller branches called dendrites.
what are dendrons responsible for ?
Dendrons are responsible for transmitting the electrical impulses towards the cell body.
What are axons?
Axons are singular, elongated fibres which are transmit impulses away from the cell body. The fibre in cylindrical in shape consisting of a narrow region of cytoplasm surrounded by a plasma membrane.
What is the myelin sheath?
The myelin sheath is a membrane rich in lipids which surrounds the axons of some neurones, speeding up impulse transmission.( ¬100m/s)
What is the node of Ranvier?
The node of ranvier is a small gap in the myelin sheath on the axon. In humans these occur every 1-3 mm. In myelinated neurones, the electrical impulses jump from one node to the next as it travels down the neurone.This allows impulses to be transported much faster.
What are schwann cells?
Schwann cells wrap around axons of motor and sensory neurons to form the myelin sheath. Each time they grow around the axon, a double phospholipid bilayer is laid down.
What are sensory neurones?
Sensory neurones transmit impulses from a sensory receptor cell to a relay neurone,motor neurone or the brain.They have one dendron which carries the the impulse to the cell body and one axon which carries the impulse away from the cell body.
What are relay neurones?
Relay neurones transmit impulses between neurones, for example, between the sensory and motor neurone.They have many short axons and dendrons.
What are motor neurones?
Motor neurones transmit impulses away from a relay neurone or sensory neurone to an effector, such as a muscle or gland. They have one long axon and many short dendrites.
What is the general nervous response pathway the electrical impulse follows?
Receptor— sensory neurone—- relay neurone— motor neurone— effector
Draw and annotate a sensory neurone.
Sensory neurone
