Nervous System Flashcards
Functions 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
Brain
Spinal Cord
Senses
Nerves
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
wrap around axons of motor and sensory neurons to form the myelin sheath
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.
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.
The CSF is produced in spaces within the brain called ventricles. CSF is constantly being produced, circulated and reabsorbed within these ventricles.
Cerebrum
Largest part of brain
Divided into 2 hemispheres
Outer cerebral cortex= “gray matter,” made of cell bodies & dendrites
Controls conscious activities
Inner cerebral medulla= “white matter,” made of myelinated axons
Frontal Lobe
Voluntary movements (walking) Reasoning & decision-making Memory Ability to predict consequences of actions Planning Verbal communication
Parietal Lobe
The parietal lobe controls:
Sensations
Visual-spatial processing
Body position
Occipital Lobe
The occipital lobe controls:
Visual processing- vision & memory of objects
Temporal Lobe
The temporal lobe controls: Memory Comprehension & pronunciation of words Sensations of smell and sound Emotional association of memories
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.
Midbrain
Also known as mesencephalon
Relays info to cerebrum
Controls body movements and postures
Pons
The Bridge!
Almost completely made of white matter that links cerebral cortex and cerebellum
Carries info from one side of brain to the other (why its called the bridge)
Central control of breathing
Temporal Lobe
The temporal lobe controls: Memory Comprehension & pronunciation of words Sensations of smell and sound Emotional association of memories
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
A cross section of the spinal cord has a “butterfly” of gray matter surrounded by white matter
Mechanoreceptors (touch)
Mechanoreceptors are a type of somatosensory receptors which relay extracellular stimulus to intracellular signal transduction through mechanically gated ion channels.
Thermoreceptors (temperature variations)
Thermoreceptors are free nerve endings that reside in the skin, liver, and skeletal muscles, and in the hypothalamus, with cold thermoreceptors 3.5 times more common than heat receptors.
Pain receptors
A nociceptor (“pain receptor”) is a sensory neuron that responds to damaging or potentially damaging stimuli by sending “possible threat” signals to the spinal cord and the brain.
Chemoreceptors (chemicals)
Chemoreceptors are specialized cell groups responsible for acquiring information about the chemical environment and subsequently conveying the information to neurons.
Photoreceptors (light)
Photoreceptors are specialized cells for detecting light. They are composed of the outer nuclear layer that contains the cell nuclei, the inner segment that houses the cell machinery, and the outer segment that contains photosensitive pigment.
Papillae
The tongue is filled with bumps called papillae. Many of these papillae contain taste buds, which contain chemoreceptors.
Malleus
hammer
Incus
anvil
Stapes
stirrup
Cochlea
boney snail-shaped structure containing membranes filled with fluid
Cornea
allows light into the eye
Pupil
muscles regulate the amount of light entering the eye
Iris
works with pupil to regulate the amount of light entering the eye
Retina
located in the back of the eye, contains thousands of photoreceptors
Lens
semi-solid disc that directs light waves towards the retina
Farsighted vs Nearsighted
farsighted- can’t see near
nearsighted- can’t see far
