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Human Biology

The Nervous System

Divisions of the Nervous System

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§  Brain and Spinal Cord §  Interneurons

§  Connecting neurons with the CNS §  Connecting sensory with motor neurons

Central Nervous System (CNS)

§  Everything lying OUTSIDE the CNS

Peripheral Nervous System (PNS)

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§  Sensory neurons

§  Carry impulses TOWARD the CNS

§  Motor neurons §  Carry impulse AWAY from CNS to an EFFECTOR organ

(muscle, gland, etc.)

PNS - composed of…

receptors

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Zombie Nervous System… §  Zombies are driven by their brains

§  Thus, the CNS must be functioning

§  Zombies have movement §  Thus,the PNS is also needed

§  But research shows that the PNS no longer functions normally.

Zombie Nervous System… §  Further research shows that the

autonomic system no longer functions §  What reasons can you give to confirm this fact?

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Zombie Nervous System… §  Further research shows that the

autonomic system no longer functions §  What reasons can you give to confirm this fact? -Autonomic deals with output to smooth muscle and glands…. As Zombies “age” they decompose further and thus loose their glandular tissue, muscle and body “tone”! - Although it is “AUTOMATIC” and zombie’s move toward rotting flesh, the do not “think” with their stomachs because often they no longer have stomachs! Just so you know!

Reflex Arc •  Main FUNCTIONAL unit of the nervous system

•  Allows us to react to internal and external stimulus

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1.  Reflex is initiated 2.  Impulse moves down the SENSORY NEURON 3.  Impulse reaches the spinal cord 4.  Impulse moves down the MOTOR NEURON

•  Stimulates the quads and inhibits the hamstrings

Practice: CNS & PNS Instructions

•  Complete the following table by writing Yes or No beneath the headings CNS and PNS

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Instructions •  Complete the following table by writing Yes or No

beneath the headings CNS and PNS

Yes

Yes

Yes

NO

NO

NO

Instructions •  Complete the following table by writing Yes or No or

inserting the correct descriptor

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Yes

Yes

Yes

NO

NO

NO

Instructions •  Complete the following table by writing Yes or No or

inserting the correct descriptor

Involuntary Voluntary

Glands, cardiac, & smooth muscle

skeletal muscle

Instructions •  Complete the following table by writing Yes or No or

inserting the correct descriptor

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Yes

noradrenalin

Yes

NO

acetylcholine

NO

Instructions •  Complete the following table by writing Yes or No or

inserting the correct descriptor

Yes NO

Glands, cardiac, & smooth muscle

Glands, cardiac & smooth muscle

The Brain

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The Brain

Pons

CEREBELLUM “Little Brain” •  Organizes outgoing motor impulses so motions are

coordinated and fluid •  Coordinates muscular activity (balance and muscle

coordination) •  Maintains equilibrium (body position and motion)

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CEREBRUM “the Brain” •  Coordinates and processes sensory input and

coordinates motor responses •  Sensation, thought processes and motor control •  Responsible for CONSCIOUSNESS and higher thinking

Thalamus •  “Switchboard”

•  Receives and routes all incoming sensory information to parts of the brain

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Corpus Callosum •  Nerve tract connecting two sides of the brain

•  Information moving from one half to the other is routed through this section

Hypothalamus •  Autonomic control center

•  Hunger, thirst, sleep, body temperature •  Endocrine Control

•  Connects brain to endocrine organs by releasing hormones that influence pituitary secretions (eg. GnRH, ADH)

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Pituitary •  Releases hormones that control ENDOCRINE system

•  Thus, brain controls functions including sexual maturity, menstruation, metabolic rate, and [water] in blood

•  ANTERIOR PITUITARY - TSH, LH, FSH •  POSTERIOR PITUITARY - stores/releases ADH, oxytocin

Medulla Oblongata •  Controls VITAL FUNCTIONS

•  Heart rate, respiration, blood pressure, many reflexive actions (coughing, vomiting, hiccups, swallowing)

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Pons •  Connects cerebellum with the cerebrum

•  Regulates respiration, sleep, bladder control, hearing, taste, eye movements, posture, facial sensation etc…..

Meninges •  Layers of tissue that surround brain and spinal cord

•  Protects the CNS

Meninges

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Zombie Nervous System… §  Zombies have no ability to regulate

there consumption of food. What part(s) of the brain is no longer functioning in Zombies?

Zombie Nervous System… §  Zombies have no ability to regulate

there consumption of food. What part(s) of the brain is no longer functioning in Zombies?

§  Answer: §  Pituitary & Hypothalamus

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A - Cross Section of a normal brain B - Cross Section of a Zombie brain

Zombie Brain…

Zombie Nervous System…

§  Finally, how do we know that zombie’s brains still have some function?

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Zombie Nervous System… §  Finally, how do we know that zombie’s brains still

have some function?

§  Answer: §  Because we need to sever the spinal cord or

destroy the brain in order to “kill” them!

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