UNIT 13: THE NERVOUS SYSTEM_Elisa_GBC_1

• Is the master controling communicating system.
• Its signaling device with body cells is electrical impulses which are rapid and cause immediate repsonses

B. Nervouse system - you got it.

The endocrine system organs produce hormones that are released into the blood

• 1. Sensory Input
• 2. Integration
• 3. Motor Output

• Monitors changes occuring both inside & outside the body.
•  * These changes are called stimuli
•  * The info gathered is called sensory input

• Processes and interprets the sensory input.
• then decides what should be done

• the effect or causes actioned by the muscles is the motor output.
• (ie. foot pressing the break pedal when you see a red light.)

• 1. Brain
• 2. Spinal cord

• 1. Cranial
• 2. Spinal Nerves

Afferent divison

To go towards

consists of nerve that send impulses to the central nervous system from various parts of the body.

Are sensory fibers delivering impluses from the skin, skeletal musles and joints.

carries impulses FROM the CNS to the effector organs, muscles and glands.

(These muscles bring about a motor response)

• 1. Somatic (body) Nervous system
• 2. Autonomic Nervous system

allows us to consciously, or voluntarily control our skeletal muscles

• Regulates events that are automatic or involuntary. 
• (ie. smooth and cardiac muscles and glands)

Involuntary nervous system

• 1. Sympathetic
• 2. Parasympathetic

• Is part of the autonomic nervous system 
• Speeding up the heartbeat and causes contraction of the blood vessels. 
• Regulates the function of the sweat glands and stimulates the secretion of glucose in the liver. 
• Sympathetic nervous system is activated especially under conditions of stress.

Sometimes called the rest and digest system Parasympathetic system conserves energy as it slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract.

• 1. Supporting cells aka Neuroglia
• 2. Neurons

• this the the nerve glue
• generally support, insulate and protect the delicate neurons

• they have swallen ends that cling to neurons, bracing them and anchoring them to their nutrient cappilary blood line
• they protect neurons from harmful substances
• help control the chemical environment in the brain by "mopping up" leaked potassium ions

• Phagocytes that monitor the health of neurons
• dispose of debris, dead brain cells and bacteria

• 1. These cells line the central cavities of the brain and spinal cord
• 2. The beating of their cilia helps circulate cerebrospinal fluid
• 3. Forms protective cushion around CNS

1. Wrap their flat extensions (proceses) around the nerve fibers, producing fatty insulating coverings called myelin shealths

Form the myelin sheaths around nerve fibers that are found in PNS

Are highly specialized cells that transmit messages from one part of the body to another

is the centre of the neuron

convey incoming messages toward the cell body are called dendrites

Conduct nerve impulese away from the cell body

• Protects and inculates the fibers
• Increases transmission rate of nerve impulese

is a tight coil of wrapped membranes that encloses the axon.

Is the outter of the Schwan cells

The gaps formed between myelin sheath cells along the axons.

Interneuron is a nerve cell that links motor and sensory neurons, and it transmits impulses between them.

one or more bundles of fibers forming part of a system that conveys impulses of sensation, motion, etc., between the brain or spinal cord and other parts of the body.

consists of dense (thick) collections of myelinated fibers (tracts)

contains mostly UNmyelinated fibers and cell bodies

bundle of nerve fibers running through the CNS

a cluster or bundle of nerve fibers

 the outer layer of the peripheral nerves contained in the human body.

It is a protective layer of tissue located around the nerves and internal organs

innermost layer of the perineurium

rapid, predictable, and involuntary responses to stimuli

Reacts to stimuli

to connect the sensory receptor and effector organ (the muscle or gland that has been stimulated)

• Is a nodule (knot) on a dorsal root that contains cell bodies of sensory neurons. 
• Is found in the afferent spinal nerves. 
• Has axon, which relays information into the CNS

Information from one neuron flows to another neuron across a synapse.  The synapse contains a small gap separating neurons. 

• The synapse consists of:
• 1. A Presynaptic ending that contains neurotransmitters, mitochondria and other cell  organelles
• 2. A postsynaptic ending that contains receptor sites for  neurotransmitters.
• 3. A synaptic cleft or space between the presynaptic and postsynaptic endings.

A nerve cell that acts as a link between sensory neurons and motor neurons

Is a cell that directly or indirectly controls the contraction or relaxation of muscles

single synapse in the spinal cord that links the transfer of information from a sensory neuron to the proper motor neuron

• A three neuron reflex arc has to do with a crossed extensor reflex arc
• (IE. When you step on a nail, your other leg extends to support your weight when you lift your other leg up off the nail) and a three neuron arc also has to do with the reflex that lifted your leg that stepped on the nail.

• 1. Cerebral Hemisphere
• 2. Diencephalon
• 3. Cerebellum
• 4. Brain Stem

The cerebral hemisphere is one half of the cerebrum, the part of the brain that controls muscle functions and also controls speech, thought, emotions, reading, writing, and learning.

White matter, like the corpus callosum, allows different parts of the brain to communicate with each other.

The brain is divided into a right and left hemisphere, and the two halves are connected by the corpus callosum

• 1. Frontal Lobe
• 2. Occipital lobe
• 3. Parietal Lobe
• 4. Temperal lobe

Concerned with reasoning, planning, parts of speech and movement (motor cortex), emotions, and problem-solving

Concerned with perception of stimuli such as touch, pressure,  temperature and pain.

Concerned with perception and recognition of auditory stimuli  (hearing) and memory (hippocampus).

Deals with many aspects of vision.

seperate large regions of the brain

Longitudinal fissures

Are elevated ridges of tissue on the cerebral hemisphere

are shallow groves on the cerebral hemisphere

seperates the frontal lobe and from the parietal lobe

separates the parietal lobes and the occipital lobes in both hemispheres

Marks the separation of the temporal lobe from the frontal and parietal lobes

Speech, memory, logical, emotional, interpretations of sensation and voluntary movement are all functions of the cerebral cortext

Parietal lobe

frontal lobe

Vision is located in the posterior (back part of brain) part of the occipital lobe

Frontal Lobe (BROCA is located in this lobe as well)

Frontal lobe

frontal lobe

frontal lobe

Frontal lobe

Location - Buried deep within the white matter of the cerebral hemisphere

Function - Body movement and coordination

• Location - encloses the shallow third ventrical of the brain
• function - is a relay station for sensory implulses UPWARD to sensory cortex

• Location: under the Thalamus
• Function: regulates body temperature, water balance and metabolism.  alont with thirst, appetite sex, etc

Location - behind the third cerebral ventricle in the midline of the brain.

• Functions:
• Secretion of the Hormone
• Conversion of Nervous System Signals to Endocrine Signals
• Causes Feeling of Sleepiness
• Influences Sexual Development

The midbrain controls visual and auditory systems as well as eye movement.

Location: Round structure that protudes below the mid brain.

• Function: pons literally means bridge
• serves as a communications and coordination center between the two hemispheres of the brain.

• * Location: Most inferior (bottom) part of brain stem
• * Function: controls heart rate
• *               Blood pressure
• *              Breathing

Location: Under the occiptal lobe of the cerebrum

function: controls skeletal muscle activity and controls our balance and equilibrium

When we drink alcohol our balance is effecte b/c it affects our cerebellum

• lengths: 17 inches long (42cm)
• where it starts: Foramen
• Where is ENDS: Just below the ribs

The collection of spinal nerves at the inferior end of the vertebral canal

in the lumbar region of the spine

• *Provides a TWO-WAY conduction path to and from the brain
• * controls numerous reflexes

• * Primarily sever head and neck
• * There are 12 pairs of nerves that can be seen on the ventral (bottom) surface of the brain

• There are 31 pairs of spinal nerves
• Formed by ventral and dorsal roots of the spinal cord
• Are located in/on the spine

It is 3 connective tissue membranse covering and protecting the CNS

• Is the outter most layer (leathery)
• Tough layer

a fluid-filled space or potential space between the dura mater and the arachnoid

• * middle meningeal layer
• * Weblike (looks like cobwebs)

attached to the inner most membrane

• Delicate
• Clings to the surface of the brain & spinal cord

• Is a watert broth similar to the make up of blood plasma. 
• The CSF is formed by blood
• CSF around the brain and spinal cord forms a watery cushion the protects the nervous system from blows and trauma

are venous channels which drain the blood from the brain

are clusters of capillaries hanging from the roof in each of the brian ventricles

Absorption of the CSF into the blood stream takes place in the superior sagittal sinus through structures called arachnoid villi

• *Are composed of the least permeable capillaries in the body.
• * Meaning very little passes through the blood brain barrier

allowing liquids or gas to pass through it

water and essential amino acids pass through these barriers

* urea, toxins, proteins, and most drugs

against fats, respiratory gases and fat soluable molecules.

This is why blood borne alcohol, nicotine, and anesthetics can affect the brain