Nervous System Flashcards
The function of the Nervous System
Detects impulses from the senses; the control center of the body
Major organs of the nervous system
Brain, spinal cord, senses, nerves
Difference between neurons and neuroglia
Neurons take up 10%, Neuroglia takes up 90%
Dendrite
Receives the nerve impulses from the senses or another neuron
Soma
Body of the neuron that holds the nucleus
Axon
The passageway for nerve impulses after the cell body; end in the axon terminal
Myelin sheath
Insulates the axon. Produced by the Schwann cells
Node of Ranvier
Impulses jump from node to node, which increases the speed of impulse
Axon terminal
The button-like endings of axons through which axons make contact with other nerve cells.
Axon
A portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. (also called a nerve fiber)
CSF
Protects the brain by preventing it from contacting the skull, maintains the blood-brain barrier, which controls homeostasis for the brain and prevents infection.
Cerebrum
The largest part of the brain, divided into two hemispheres
Frontal Lobe
Voluntary movements, reasoning, and decision-making, memory, planning, verbal communication
Parietal Lobe
Sensations, visual-spatial processing, body position
Occipital Lobe
Visual processing- vision & memory of objects
Temporal Lobe
Memory, understanding words/language, sensations of smell and sound, and emotional association of memories
Thalamus
Relays sensory impulses to the cerebral cortex for processing and sorting
Hypothalamus
Controls hormones released by the pituitary gland, also responsible for autonomic processes
Brainstem
Has 3 regions, located between the cerebrum and spinal cord
Midbrain
Relays info to the cerebrum, control body movements, and postures
PONS
BREATHING. Carries info from one side of the brain to the other (that’s why it is called a bridge)
Cerebellum
MOVEMENTS. (also called the baby/little brain!)
Spinal Cord
Comes from the medulla oblongata
Spinal Cord
Comes from the medulla oblongata, Relays impulses from the PNS to the brain
Hair Follicle Receptor
Hair follicle receptors are rapidly adapting receptors that respond better to something brushing across the skin rather than pressure.
Ruffini’s Corpuscle
These receptors adapt slowly to pressure which results in stretching of the skin. They record the sustained presence of pressure on the skin.
Pacinian Corpuscle
Responds to mechanical deformation
Merkel’s Disk
The Merkel disc is the main type of tactile end-organ for sensing gentle touch and is essential for sophisticated sensory tasks, including social interaction, environmental exploration, and tactile discrimination.
Free Nerve Ending
Free nerve endings are sensitive to painful stimuli, to hot and cold, and to light touch. They are slow to adjust to a stimulus and so are less sensitive to abrupt changes in stimulation.
Malleus (Hammer)
The malleus functions with the other bones to transmit vibrations from the eardrum to the inner ear.
Incus (Anvil)
The incus transmits vibrations from the malleus to the stapes. The vibrations then move to the inner ear. Conditions that affect the incus often affect the other ossicle bones.
Stapes (Stirrup)
The stapes transmit sound vibrations from the incus, another little bone in the middle ear, to the oval window adjacent to the inner ear. The stapes is the smallest bone in the body.
Cochlea
A bony snail-shaped structure containing membranes filled with fluid.
Cornea
The cornea is made of thick, transparent tissue
Function: allows light into the eye
Pupil
The pupil is the opening in the center of the iris
Function: muscles regulate the amount of light entering the eye
Iris
The iris is located behind the cornea. It is the colored part of the eye.
Function: works with the 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
Eye-ball is too short. Farsightedness is a common vision condition in which you can see distant objects clearly, but objects nearby may be blurry.
Nearsighted
Nearsightedness is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry.
