Nervous System Flashcards
Function of nervous system
The function of the nervous system is to detect impulses from the senses; control center of the body
Major organs of nervous system
Major Organs: Brain Spinal Cord Senses Nerves
Difference between neurons and neuroglia
Neurons (make up 10% of the nervous system)
Neuroglia (“nerve-glue”, make up 90% of the nervous system)
Dendrite
receive the nerve impulses from the senses or another neuron
Soma
body of the neuron that holds the nucleus
Schwann cells
Allows myelin sheath to grow
Node of Ranvier
impulses jump from node to node, which increase speed of impulse
Myelin
insulates the axon. Produced by the Schwann cells
Axon
passageway for nerve impulses after cell body; end in axon terminal
Axon terminal
the button-like endings of axons through which axons make contact with other nerve cells.
(5) Different types of sensory receptors
Merkel’s disk
touch
(5) Different types of sensory receptors
Hair follicle receptor
touch
(5) Different types of sensory receptors
Free nerve ending
pain and temperature
(5) Different types of sensory receptors
Ruffini’s corpuscle
touch and pressure
(5) Different types of sensory receptors
Pacinian corpuscle
pressure
(3) Tiny bones in your ear and nickname
malleus, incus, and stapes
These are commonly known as the hammer, the anvil, and the stirrup.
They amplify the sound waves to the inner ear through a membrane called the oval window.
Cochlea
a bony snail-shaped structure containing membranes filled with fluid.
Cornea
Cornea is made of thick, transparent tissue
Function: allows light into the eye
Pupil
Pupil is the opening in the center of the iris
Function: muscles regulate the amount of light entering the eye
Low light- pupil wide open
High light- pupil nearly closed
Iris
The iris is located behind the cornea. It is the colored part of the eye.
Function: works with pupil to regulate light entering the eye
Retina
The retina, located in the back of the eye, contains thousands of photoreceptors.
Lens
The lens is a semi-solid disc that directs light waves towards the retina.
It is controlled by ciliary muscles and suspensory ligaments.
Farsighted vs Nearsighted (what is the difference?)
farsighted- eyeball is to short
nearsighted- eyeball is to long
Papillae
The tongue is filled with bumps called papillae. Many of these papillae contain taste buds.
CSF
The cerebrospinal fluid protects the brain by preventing the it from contacting the skull.
It also maintains the blood-brain barrier, which controls homeostasis for the brain and prevents infection.
Cerebrum
Largest part of brain
Divided into 2 hemispheres
(4) Lobes of cerebrum
The cerebrum is divided into 4 lobes, frontal lobe, parietal lobe, occipital lobe, and temporal lobe.
Thalamus
2 bulb-shaped halves in the center of the brain
Relays sensory impulses to the cerebral cortex for processing and sorting
Hypothalamus
Controls hormones released by pituitary gland (often called the “master endocrine gland”)
Responsible for autonomic processes (body temperature, hunger, sleep, thirst, blood volume, etc)
Brainstem
Located between the cerebrum and spinal cord. Also known as mesencephalon
Relays info to cerebrum
Controls body movements and postures
(3) Regions of Brainstem
Broken into three regions:
Midbrain
Pons
Medulla Oblongata
Cerebellum
Second largest part of brain Near back of skull Responsible for coordinating the movements directed by the cerebrum so that they are graceful and efficient All involuntary movements Aids in “muscle memory”
Spinal Cord
Extends from the medulla oblongata
31 pairs of spinal nerves branch out from the spinal cord, connecting to all parts of the body
Relays impulses from the PNS to the brain
