1. The Nervous System
Chapter 11

2. Parts of the Nervous System
CNS: brain & spinal cord
Receives & processes information,
initiates effector responses
Central N.S.
Brain
Spinal cord
Peripheral N.S.
Motor
Sensory
Autonomic
- parasympathetic
- sympathetic
Somatic
PNS: nerves outside CNS
Sensory (body- receptors CNS)
Motor (CNS  body- effector cell)
Somatic division: controls skeletal muscle
Autonomic division: controls cardiac muscles, smooth muscles and glands
Parasympathetic (calming)
Sympathetic (fight-or-flight)

3. From Cells to Organ Systems
Purpose: transmit, control, maintain, process
neuron: nerve cell
Sensory: sends info to CNS
Motor: carries CNS directions to the body
Interneuron: relays messages between sensory and motor neurons
glial cell: of fifferent types; supports/protects neurons
Some form myelin sheaths- e.g. Schwann cells (PNS); oligodendrocytes (CNS)
speeds up transmission, & helps damaged/severed axons regenerate -
Q: How does structure go with function?

4. Myelinated neuron
Figure 11.7a

5. From stimulus to response
Sensory neuron
Dendrite
Receptor
Cell body
Axon
Axon terminals
Axon bulb
Dendrites
Axon hillock
Interneuron
Brain and spinal cord
Motor neuron
Skin
Muscle
Impulse direction
Figure 11.2
Stimulus triggers sensory receptor on dendrite of sensory neuron
The impulse is sent towards the cell body
Axons transmit the signal away from the cell body eventually to interneuron
Interneuron “processes” info then sends impulse to a motor neuron
Motor neuron transmits to an effector (muscle or gland)
Muscle or gland responds

6. Synapse Is a junction, between neurons or neuron and effector cell
Between neurons it consists of:
1.Axon terminal of presynaptic (transmitting) neuron 2.postsynaptic (receiving) neuron
3.The two neurons are separated by a space (synaptic cleft)
The nerve impulse triggers the release of neurotransmitters from vesicles in axon teminal
Neurotransmitters will lead to initiation of an action potential ( nerve signal in second neuron)
Figure 11.8

7. Central Nervous System; brain and spinal cord
Figure 11.13

8. Outer layer of cerebrum
Cerebral cortex
Outer layer of cerebrum
outer region is grey matter (processing, etc.): contains functional areas
White matter
Inner region is white matter (receiving/sending signals)
Parietal lobe
Interprets sensory
information from skin
Occipital lobe
Processes visual
information
Temporal lobe
Interprets auditory
information
Comprehends language
Frontal lobe
Initiates motor activity
Responsible for speech
Conscious thought
Figure 11.16b

9. Central Nervous System
Central Nervous system: brain and spinal cord
CNS protection
Bone: skull and vertebrae
Meninges: dura mater, arachnoid, and pia mater
Cerebrospinal fluid: protective cushion- produced by capillaries
Blood–brain barrier: allows limited material across membrane of capillary cells

10. The brain processes and acts on information
Figure 11.15
FOREBRAIN
Cerebrum
• Coordinates language
• Controls decision making
• Produces emotions and conscious thought
MIDBRAIN
• Relays visual and auditory inputs
Corpus callosum
• Bridges the two cerebral hemispheres
Limbic System; Involved in emotions
Thalamus
• Receives, processes and transfers motor information/sensations
HINDBRAIN
Pons
• Connects cerebellum, spinal cord with higher brain centers •
Medulla oblongata
• Has vital centers for
breathing, heart rate
Cerebellum
• Controls basic and skilled movements
Coordinates movement
Q: Which part of the brain classifies humans as “intelligent” beings?

11. Peripheral Nervous System
Transmits information between tissues and CNS
Mediated via nerves (collection of neurons)
Nerve function depends on its origin and destination
Two types of peripheral nerves
12 cranial nerves: connects directly to the brain
31 spinal nerves: connects to the spinal cord
Sensory neurons enter spinal cord
Motor neurons exits spinal cord

12. Peripheral Nervous System
PNS Somatic division controls skeletal muscles
controls voluntary movements
Includes spinal reflexes
Involuntary responses
Does not require conscious thought
Central N.S.
Brain
Spinal cord
Peripheral N.S.
Motor
Sensory
Autonomic
- parasympathetic
- sympathetic
Somatic
-skeletal muscle
-spinal reflexes

13. Peripheral Nervous System
PNS Autonomic division:
Sympathetic and parasympathetic motor divisions
Central N.S.
Brain
Spinal cord
Peripheral N.S.
Motor
Sensory
Autonomic
- parasympathetic
- sympathetic
Somatic
-skeletal muscle
-spinal reflexes
Oppose each other
Helps maintain homeostasis
Control functions in cardiac muscles, glands, smooth muscles, etc.
Sympathetic stimulates/arouse
Parasympathetic relaxes

14. Sympathetic and parasympathetic motor divisions