This document provides an overview of the main structures and functions of the brain and nervous system. It discusses the four lobes of the brain and their functions, as well as the limbic system and its role in emotions. It also describes the basic anatomy and cell types of the brain and spinal cord, including neurons, glial cells, grey matter, and white matter. Key functions such as processing sensory information and memory are highlighted.

1. Warm-up!

2. The Nervous System
Brain Review, Nerve & Spinal Cord Anatomy

3. The Lobes
 Frontal Lobe
 Area around your forehead
 Involved in purposeful acts like judgment, creativity, problem solving, and
planning.
 Parietal Lobe
 Top back area of the brain
 Processes higher sensory and language functions
 Temporal Lobe
 Left and right side above and around the ears
 Primarily responsible for hearing, memory, meaning, and language.
 Some overlap in functions of the lobes.
 Occipital Lobe
 Back of the brain
 Primarily responsible for vision

4. The Limbic System
Emotional Center
 Hypothalamus  Hunger, thirst,
body temperature, pleasure;
regulates pituitary gland (hormones)
 Pituitary  “Master Gland”
 Stimulates other glands to produce hormones
 Amygdala  Aggression (fight) and
fear (flight)
 Hippocampus  Memory
processing

5. Facts about the Brain
 Weighs approximately 3 pounds
Mostly water - 78%
Fat - 10%
Protein - 8%
 Soft enough to cut with a butter knife
 Grapefruit-sized organ
 Outside of the brain
Convolutions or folds
Wrinkles are part of the cerebral cortex
Folds allow maximum surface area

6. Brain
There are two types of
brain cells:
 Glial cells
 Neurons
Brain matter has two
colors
 Grey Matter
 White Matter

7. Glial Cells
Function:
To surround neurons and hold them in place
To supply nutrients and oxygen to neurons
To insulate one neuron from another
To destroy pathogens and remove dead
neurons.
90% of the brain cells
Less known about glia cells
No cell body

8. Neurons
Neurons (Greek word meaning bowstring)
100 billion neurons in human brain
Neurons essential to performing the brain's
work
Consist of a compact cell body, dendrites, and
axons

9. Neurons
 Neurons (brain cells) make connections between
different parts of the brain.
 Information is carried inside a neuron by electrical
pulses and transmitted across the synaptic gap
from one neuron to another by chemicals called
neurotransmitters.
 Learning is a critical function of neurons.

10. Dendrites and Axons
 Dendritic branching helps make connections between
cells.
 As cells connect with other cells, synapses occurs.
 New synapses appear after learning.
 Repeating earlier learning makes neural pathways more
efficient through myelination (fatty substances formed
around axons)

11. Grey Matter
 Consists mostly of cell
bodies of Neurons
 Makes up about 40% of
the brain content
 The processing taking
place in this area consists
mostly of sensory
information; speech,
hearing, feelings, vision,
and memory.

12. White Matter
 Consists of nerve fibers or
axons of neurons.
 The white color is due to
the myelin sheath.
 Allows communication to
and from grey matter areas
and between the brain and
body.
 Controls automatic
functions (heart rate,
breathing, temperature
regulation, etc.)

13. Meninges
3 membranes that cover and protect the brain
and spinal cord
Dura mater – outer layer
Arachnoid membrane – middle, delicate layer
Pia mater – attached to the brain and contains
blood vessels that nourish the nerve tissue

14. Spinal Cord
 Spinal cord
Continues down from the medulla oblongata
Surrounded and protected by vertebrae
Responsible for many reflex actions and
carrying afferent and efferent nerves
 Spinal nerves carry messages to and from the
spinal cord and are mixed nerves (both afferent
and efferent)

15. Cross Section of Spinal Cord
11-7

16. Spinal Tract
• groups of axons with cell bodies in the
same area that are headed to the same
destination
Generalizations
1. Most cross from one side of the
spinal cord to the other (decussate)
2. contain 2 or more neurons
3. Somatotopy – the locations of the
tracts in the spinal cord reflects the
mapping of the body
4. All tracts are paired with one on
each side of the spinal cord

17. Ascending Pathways
Usually contain 3 successive neurons
First Order Neurons – body in ganglion (dorsal or cranial)
-- get impulses from skin and proprioceptors in the
spinal cord to the brain stem
Second Order Neurons – body in dorsal horn or medullary
nuclei
-- transmit impulse to thalamus or cerebellum
Third Order Neurons – body in thalamus
--send info to cortex
Sensory

18. Descending Tracts
Motor
Direct Pathway – originate in cortex
• No synapses until they reach the spinal cord
• Interacts with interneurons or in the ventral horn
• Activates skeletal muscle to do skilled movements (writing)
Indirect Pathway (multineuronal)
• all other descending tracts
• usually rely of reflexes
• regulate
•Axial muscle for balance and posture
•Muscle controlling course limb movement
•Head, neck, and eye movement

19. Reflex Pathways
 Receptors in the skin send
signals through sensory
neurons.
 Signals travel to the spinal
cord and up to the brain.
 Signals from the brain
travel back down the spinal
cord.
 Motor neurons from the
spinal cord send signals to
muscles to move.