Chapter 15, Coordination Flashcards
What is an axon?
A long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses known as action potentials away from the nerve cell body.
What is the function of an axon?
To transmit information to different neurons, muscles, and glands.
How do neurons work?
1) Electrical impulse is sent from a nerve receptor and travels along the axon
2) At nerve ending there is a gap called the synapse. It works as the electrical impulse and triggers the release of neurotransmitters.
What is a reflex arc?
- Pathway which imp. are transmitted from receptor to an effector without involving the conscious parts of brain.
- Imp. travel from sensory to relay ( not always) to motor.
- In spinal cord, imp. are passed onto other n. that goes up to brain. At same time passing through m.n.
- Therefore effector acts before brain could process, hence its a reflex action.
What are the three types of neurons?
Sensory.
Relay.
Motor.
What is a stimulus?
Change in an organisms surroundings.
What are receptors?
Something which detects changes. Converts stimulus energy into electrical impulses.
What is an effector?
Muscle or gland that brings a response to the stimulus.
What are electrical impulses passed through?
The nervous system and back to the effector.
Exteroreceptors:
Detect stimuli coming form the outside of the body.
Interceptors:
Detect stimuli. All stimuli represents forms of energy.
Sensation:
Involves converting this energy into a change in the membrane potential of sensory receptors.
Sensory receptors perform four functions:
Sensory transduction
Amplification
Transmission
integration
Types of sensory receptors (five categories):
- Mechanoreceptors
- Chemoreceptors
- Electromagnetic receptors
- Thermoreceptors
- Pain receptors
Mechanoreceptors:
Sense physical deformation caused by a stimuli such as pressure, stretch, motion, and sound.
Chemoreceptors:
- Include general receptors that transmits information about the total solute concentration of a solution.
- Specific receptors that respond to individual kinds of molecules.
Electromagnetic receptors:
Detect various forms of electromagnetic energy such as light, electricity, and magnetism.
Thermoreceptors:
Respond to heat or cold. Help regulate body temperature by signaling both surface and body core temperature.
Pain receptors:
Naked dendrites in the epidermis. Respond to excess heat, pressure, or specific classes of chemical released from damaged or inflamed tissues.
The autonomic system:
Sympathetic and the parasympathetic systems.
The sympathetic system:
Puts the body in the alarm readiness and increases metabolism, correlates with the “fight-or-flight” response while the parasympathetic systems generally stimulates the body to do more relaxing activities, such as digestion, promotes a return to self-maintenance functions.
Sensory neurone:
Transmit impulses from receptors to CNS.
Ganglion:
- Cell body near source of stimulus or swelling of spinal cord.
Intermediate Neurone:
- Transmit impulse from sensorn to motor neurone
- Found entirely in CNS
Motor Neurone:
- Transmit impulses from CNS to effector.
- Cell body lines within CNS and contains the nucleus.
- Dark specs in c.p. are rough ER regions.
Myelin:
- Made by Schwann cells.
- Axons of m.n and s.n surrounded by thick dark rings of myelin.
Schwann Cells:
- Specialised Cells.
- Made of lipid and some proteins.
- Wrap themselves around axons enclosing it in many layers. Uncovered regions between these cells = Nodes of Ranvier.
