By: Allie Dunn & Sarah Leitnaker

Evolution of Nervous system

Hydra (Cndarian)- have one or more nerve net, made up of neurons.

Flatworm (planarians)- have ladder like nervous system with two nerve cords that run the length of

the body.Connected by transverse nerves Cephalization Ganglion- a cluster of neurons

Hydra and Flatworm

Evolution of Nervous system

Earthworms (annelids) (Also molluscs and arthropods/insects)

True nervous systems A brain, well developed sense organs,

multiple ganglia, and increased number of neurons.

Evolution of Nervous system

Humans (vertebrates)-Central nervous system with

brain and spinal cord With ascending

and descending tracts. Peripheral nervous systems

Neurons

Cell body, dendrite, and axon Bundled axons form nerves and are

sometimes covered by myelin sheath Spiral neuroglia form myelin sheath

membrane.

Types of Neurons Motor (efferent):

Nerve impulses for CNS to musclesShape- have many dendrites and a single

axon (multipolar). Sensory (afferent):

Takes impulses from sensory receptors to CNSCell body divides into two directions, periphery CNS

(unipolar).

Interneurons: Only CNS Typical multipolar

Transmission of nerve impulses

At resting potential the axon has negative voltage

Action potential gated channels allow positive sodium ions to move freely into axon, voltage becomes positive.

Myelinated axons: action potential concentrated at the nodes.*refractory period

Synapse

Gap in between neurons (synaptic cleft) Neurotransmitter carry impulses across

synaptic cleft. They are released when calcium gates are open.

The neurotransmitters bind with the receptors.

Neuromodulators block the neurotransmitter or modifies its response.

Intermission

Brain and Spinal Cord

Protected by bone i.e. skull and vertebrae

Wrapped in meninges, three protective membranes.

Spaces in between are filled cerebrospinal fluid

Spinal Cord

Bundle of nerve tissue from brain to below rib cage.

Reflex action center and communication.

Brain

Four chambers called ventricles Cerebrum is the largest portion in

humans. Communicates and coordinates activities in the brain.Divided into lobes.

DiencephalonHypothalamus regulates hunger sleep and

temperature. And controls the pituitary gland.Thalamus receives sensory input.

Brain

Limbic system: blends emotions and mental functions.

Two different parts: Hyppocampus: awareness of past

experiences Amygdala: emotional

overtones on these

experiences

Peripheral Nervous System

Outside central nervous systems with nerves.

Cranial nerves and spinal nerves and be sensory or motor.

Somatic system: serves the skin, joint, and skeletal muscles. Reflex arc: sensory receptors generate

nerve impulses. Info is integrated. Impulses travel along motor axons to an effector which brings about a response.

Autonomic System

Regulates cardiac and smooth muscles. Involuntary Use two neurons and one ganglion for

each impulse. Sympathetic division for emergency

situations.Parasympathetic division for relaxed state.

•Degenerative disease process that affects the basel ganglia of the brain •Caused by a deficiency of the neurotransmitter and aging

•Effects are a tremor, rigidity, and difficulty with spontaneous movements.

• Also expressionless face, monotone voice and a shuffling walk.

•A loss or deficiency of motor control

•Caused by injury to the brain before, during or after birth.

•Can also be caused by hypoxia, jaundice, and infection.

•Effects are involuntary spasms and lack of balance.

•Intelligence, posture and speech are frequently impaired.

•May also be associated with visual impairment, reduced hearing and behavioral problems

•May have fixed abnormalities

•Associated with a deficiency of ACh.

•Form of dementia that gets worse overtime.

•Affects memory, thinking and behavior.

• Causes abnormal clumps (amyloid plaques) and tangled bundles of fibers (neurofibrillary tangles).

•There is no cure

•Three different stages: •Mild•Moderate •Severe