A&P Lab Nervous System Quiz # 4

pia mater

"gentle mother" is composed of delicate connective tissue and richly invested with tiny blood vessels.

Dura mater

"tough mother" strongest meninx. it is a two-layered sheet of fibrous connective tissue.

endoneurium

(endoneurial sheath, or Henle's sheath) is a layer of thin connective tissue around the myelin sheath of each myelinated nerve fiber. Its component cells are called endoneurial cells. Additional sheath that surrounds the myelin sheath surrounding each fiber within a nerve it insulates from the neuron process adjacent to it (delicate)

Define nerve

A bundle of axons in the peripheral nervous system. Found in the brain, and spinal cord. Spinal nerves carry impulses to and from the spinal cord and the cranial nerves carry impulses to and from the brain.

Explain the importance of myelin.

A sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons. Increases the transmission speed of the nerve impulses.

What are the two major protective coverings of the nervous system?

Bone and meninges.

Be able to label and explain the function of:

Cell body, Axon, Dendrites, Schwann Cells, Node of Ranvier, Terminal Axon

Plexus

Cervical Plexus - Ventral Rami of spinal nerves (C1-C5) Phrenic Nerve: innervates diaphragm, irritation causes hiccups. Shingles: Herpes, attacks dorsal root spinal nerves and sensory ganglia of cranial nerves. Brachial Plexus - Pectoral girdle & upper limbs (radial nerve). Lumbosacral plexus - lower limbs, Lumbar plexus: femoral and obturator nerves. Sacral Plexus: Sciatic nerve.

Cell body (soma)

Contains the nucleus, and provides the life processes of the entire cell. Integrates the information received by the dendrites.

meninges

Cover and protect the CNS. Protect blood vessels and enclose venous sinuses. Contain cerebrospinal fluid. Form partitions is the skull. The three layers are dura mater, arachnoid mater, pia mater.

How many cervical, thoracic and lumbar nerves are there?

Humans have 31 left-right pairs of spinal nerves, each roughly corresponding to a segment of the vertebral column: Cervical - 8 pairs, C1 to C8. Thoracic - 12 pairs, T1 to T12. Lumbar - 5 pairs, L1 to L5.

The nervous system is comprised of two cell types. What are these two cell types?

Neurons (nerve cells) - that are excitable and transmit electrical signals. Process, integrate and transmit information recieved. Neuroglia (glia) - are supporting cells, small cells that surround and wrap the more delicate neurons.

Explain the difference between the two types of cells found in the nervous system.

Neurons conduction of nerve impulses whereas neuroglia are supportive cells of the nervous system.

Define sensory neuron and motor neuron. Also, give another name for the two of them.

Sensory (afferent) neurons - consists of nerve fibers (axons) that convey impulses to the CNS. Motor (efferent) neurons -transmits impulses from the CNS to effector organs.

Arachnoid mater

the middle meninx, forms a loose brain covering. It is separated from the dura mater by a narrow serous cavity, the subdural space.

Define plexus (network)

Ventral rami form plexus. Nerve plexus occur in the Cervical, Brachial, Lumbar, and Sacral regions and serve the limbs. Within, fibers from ventral rami criss-cross one another and become redistributed.

Node of Ranvier

a naked portion of a mylinated axon,between adjacent oligodendroglia or Schwann cells

Dendrites

bring information to the neuron.

Terminal Axon

conducts the nerve impulses, this causes neurotransmitters to be released.

perineurium

the sheath of connective tissue surrounding a bundle (fascicle) of nerve fibers within a nerve.

epineurium

is the outermost layer of dense irregular connective tissue surrounding a peripheral nerve. It usually surrounds multiple nerve fascicles as well as blood vessels which supply the nerve.

Axon

sends information to other neurons. The 'highway of the neuron'.

Schwann Cells

supporting cells a cell in the peripheral nervous system that is wrapped around a myelinated axon. performs the same function for the PNS as the Oligodendrocytes do for the CNS