Function of nervous system
Detects impulses from senses; control center of the body
Major organs of nervous system
Brain, spinal cord, senses, nerves
Difference between neurons and neuroglia
Neurons- make up 10% of nervous system
Neuroglia- “nerve glue”, make up 90% of nervous system
Dendrite
Receives the nerve impulses from the senses or another neuron
Soma
The 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 increases 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
Button-like endings of axon through which axons make contact with other nerve cells
CSF (Cerebrospinal Fluid)
- Between the arachnoid layer and the pia mater is the cerebrospinal fluid (CSF)
- The cerebrospinal fluid protects the brain by preventing the it from contacting the skull
Cerebrum
- Largest part of brain
- Divided into 2 hemispheres
- Outer cerebral cortex= Gray matter, made of cell bodies and dendrites
- Inner cerebral medulla= White matter, made of myelinated axons
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
- Responsible for autonomic processes (body temperature, hunger, sleep, thirst, blood volume, etc)
Brainstem
- Located between the cerebrum and spinal cord.
- Broken into three regions
Brainstem (midbrain)
- Also known as mesencephalon
- Relays info to cerebrum
- Controls body movements and postures
Brainstem (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
Brainstem (Medulla Oblongata)
- Located above the spinal cord
- Transmits impulses between spinal cord and the brain
- Controls blood pressure, heart rate, swallowing, and coughing
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
Frontal lobe
- Voluntary movements (walking)
- Reasoning & decision-making
- Memory
- Verbal communication
Parietal lobe
- Sensations
- Visual-spatial processing
- Body position
Occipital lobe
-Visual processing: vision and memory of objects
Temporal lobe
- Memory
- Comprehension & pronunciation of words
- Sensations of smell and sound
