Quiz 1; Part A

Effectors (Motor/Efferent Division)

Organs that carry out effects of nervous system are commonly called _____.

Nissl Bodies ( Rough ER)

Protein synthesis. Supports the high level biosynthetic activity of the cell body (soma).

Regeneration tube

Schwann cells and basal lamina form a ______.

Nervous System

Seat of consciousness, personality, learning and memory.

Microglia (CNS)

Small and scarce cells. Activated by injury into wandering PHAGOCYTIC cells within CNS. Ingest disease-causing microorganisms, dead neurons, and cellular debris.

unmyelinated

Small axons in CNS and PNS are usually _____.

Mitochondria

Supply energy required for high metabolic activity.

Regeneration

_____ or replacement of damaged tissue is nearly NONEXISTENT in CNS and is LIMITED in PNS; neural tissue can regenerate only if cell body remains intact.

NEUROGLIAL CELLS, Structure-Function Core Principle

______ are able to divide and full in space left behind when neuron dies; form of each type of neuroglial cell is specialized for its function, another example of the ______.

Ependymal cells (CNS), Cerebrospinal Fluid

______ are ciliated cells that line hollow spaces found within CNS; function to manufacture and circulate ______.

Bipolar Neurons, eye and olfactory

______ are composed of ONE axon and ONE dendrite and a cell body BETWEEN them. Can be found in ______ and ______ epithelium in nasal cavity.

Motor or Efferent neurons, multipolar

______ carry information AWAY from cell body in CNS to MUSCLES and GLANDS; mostly ______.

Interneurons or Association neurons, CNS

______ relay information WITHIN ______ BETWEEN sensory and motor neurons;.

Spinal Cord (CNS)

begins at foramen magnum and continues through vertebral foramina of first cervical, to first or second lumbar vertebra. - Made up of MILLIONS of neuron; much fewer than the brain. - Enables brain to COMMUNICATE with most of body below head and neck.

Sensory or Afferent neurons

carry information TOWARD CNS; neuron cell bodies in PNS receive information from sensory receptors and relay information via axons to brain or spinal cord. Usually, PSEUDO-UNIPOLAR or BIPOLAR.

White Matter

composed of MYELINATED axons that appear white.

Neurofibrils

composed of intermediate filaments of cytoskeleton; provide structural support that extends into neuron processes.

Gray Matter

composed of neuron cell bodies, UNMYELINATED dendrites and axons that appear gray.

Neurons

excitable cell type responsible for sending and receiving signals in form of action potentials.

Neurolemma (PNS)

found on outer surface of a myelinated axon in PNS. Composed of Schwann cell nucleus, organelles, and cytoplasm.

Satellite cells (PNS)

found surrounding cell bodies of neurons in PNS to provide supportive functions.

Node of Ranvier

gap between adjacent neuroglia; where myelin sheath is absent.

Sensory Functions (Afferent)

gather information about internal and external environments of body. Somatic and Visceral.

Pseudo-unipolar Neurons

have only one FUSED axon that extends from soma and divides into TWO processes: one process carries sensory information from sensory receptors to cell body; other process carries sensory information related to PAIN, TOUCH, and PRESSURE.

Oligodendrocytes (CNS)

have radiating processes with flattened sacs that wrap around axons of nearby neurons to form myelin. Provide myelination in CNS.

Brain (CNS)

is made up of BILLIONS of nerve cells or neurons; protected by bones of skull.

Astrocytes (CNS)

large star shaped cells - Anchor neuron and blood vessels in place - Facilitate transport of nutrients and gases between blood vessels and neurons; regulate Extracellular environment of brain. - Blood-brain barrier - Repair damaged brain tissue by rapid cell division

Multipolar

make up MOST of neurons in body.

Cell Body (Soma)

most METABOLICALLY active region of neuron. Manufactures all proteins needed for whole neuron. Surrounds the organelles of the cell.

(Timing of myelination) Early, PNS: Later, CNS

myelination begins _____ in fetal development in _____ and much _____ in the _____. Very little myelin present in brain of newborn.

Neuroglia or Neuroglial Cells

not only provide structural support and protection for neurons but also maintain their environment.

Number of Axons myelinated Multiple, CNS : Single, PNS

oligodendrocytes have MULTIPLE processes that can provide myelination for _____ axons in CNS; while, Schwann cell only provides myelination for _____ axon in PNS.

Nervous System

performs millions of tasks simultaneously every second.

Axolemma

plasma membrane that surrounds axon and it's cytoplasm or AXOPLASM.

Myelination

process that forms myelin sheath from plasma membranes of neuroglial cells; wrap themselves around axon forming multiple layers of membrane. (myelin).

Schwann cells (PNS)

provides Myelination in PNS.

Axon Hillock

region where axon originates from cell body.

Internodes

segments of axon that are covered by neuroglia.

Telodendria

small branches that arise from axon and axon collaterals near where these extensions end.

Multipolar Neurons

with a SINGLE axon and MULTIPLE dendrites. 99% of all neurons.

Cranial Nerves

12 pairs of nerves traveling back to or from BRAIN.

Sensory/Afferent neurons, Interneurons/Association neurons, Motor/Efferent neurons

3 Functional Groups of Neuron

Receptive, Conducting, and Secretory Region

3 main functional regions of neurons

Spinal Nerves

31 pairs of nerves traveling back to or from SPINAL CORD.

CNS and PNS

Anatomical divisions of the Nervous System.

Wallerian Degeneration

Axon and myelin sheath degenerate DISTAL to injury, a process facilitated by phagocytes called _____.

Axon Collaterals

BRANCHES that EXTEND from main axon.

Central Nervous System (CNS)

Brain and spinal cord is part of what division of the nervous system?

Autonomic Nervous System/Visceral Motor Division (Motor Functions)

Consists of neurons that carry signals to thoracic and abdominal viscera. Critical for maintaining HOMEOSTASIS. Regulates secretion of certain GLANDS, contraction of SMOOTH MUSCLE in heart; INVOLUNTARY control (aka involuntary motor division).

Secretory Region

What region of neuron includes axon terminal?

Conducting Region

What region of neuron includes axon?

Receptive Region

What region of neuron includes dendrites and cell body?

Axon

Each neuron has only one _____.

Sensory functions, Integrative functions, and Motor functions.

Functional Divisions of The Nervous System

Proximal

Growth processes form from the _____ end of the axon.

Nervous System

Homeostasis: Respiratory rate, blood pressure, body temperature, blood pH and sleep/wake cycle.

Golgi Apparatus

Vesicular transport.

Motor Functions

actions performed in response to integration; performed by motor or efferent division of PNS; can be further subdivided into SOMATIC and AUTONOMIC (VISCERAL) efferent divisions, based on organs that neurons contact.

Integrative Functions

analyze and interpret incoming sensory information to determine an appropriate response. - 99% of integrated sensory information is subconsciously disregarded as unimportant. - Remaining sensory stimuli that CNS does respond to and generally leads to a motor response.

Dendrites

are short, branched processes; RECEIVE input from other neurons, which they transmit to toward cell body in form of electrical impulses. Each neuron have multiple _____.

Axon Terminals or Synaptic bulbs

arise from telodendria; components that communicate with a target cell.

Myelin Sheath

composed of repeating layers of plasma membrane of schwann cell or oligodendrocyte in PNS and CNS respectively.

Peripheral Nervous System (PNS)

consists of all nerves in body OUTSIDE protection of skull and vertebral column.

Nerves (PNS)

consists of axons of neurons bundled together with blood vessels and connective tissue; carry signals to and from CNS. Classified based on origin or destination.

Motor/Efferent Division

consists of motor neurons that carry out motor functions; travel from brain and spinal cord via cranial and spinal nerves. AWAY from the brain.

Somatic Sensory Division (Sensory Functions)

consists of neurons that carry signals from skeletal muscles, bones, joints, and skin. Also transmits signals from organs of vision, hearing, taste, smell, and balance. Also called as Special sensory division.

Visceral Sensory Division ( Sensory functions)

consists of neurons that transmit signals from viscera (organs) such as heart, lungs, stomach, kidneys, and urinary bladder.

Somatic Motor Division (Motor Functions)

consists of neurons that transmit signals to SKELETAL MUSCLE; under VOLUNTARY control (aka voluntary motor division).

Cytoskeleton

contains microtubules; provide structural support and a means for chemical transportation between cell body and axon.

Nervous System

controls our perception and experience of world. Directs voluntary movement.

Neuron Processes

cytoplasmic extensions that originate at cell body and include dendrites and axons; allow neurons to communicate with other cells.