14. Nervous Tissue Flashcards by Brandon Pum

Function of Nervous system

Gather information from stimuli by sensory receptors
Process the information
Produce a response by activating effector organs (muscles or glands)

How well did you know this?

Not at all

Perfectly

The nervous system is organized into:

Central nervous system (CNS) and peripheral nervous system (PNS)

How well did you know this?

Not at all

Perfectly

CNS consists of

Brain and spinal cord

Integrating and command center of NS

How well did you know this?

Not at all

Perfectly

PNS consists of

Cranial nerves, spinal nerves, and ganglia

Mostly nerves that carry signals to and from CNS

How well did you know this?

Not at all

Perfectly

PNS is divided into:

Sensory and motor divisions

How well did you know this?

Not at all

Perfectly

Sensory division consists of

Somatic sensory, visceral sensory, and special sensory

How well did you know this?

Not at all

Perfectly

Characteristics of somatic sensory

Sensations on skin or in body wall (touch, pain, pressure, pulled muscle, etc.)
Proprioception (detect position and movement)

How well did you know this?

Not at all

Perfectly

Characteristics of visceral sensory

Sense stimuli from viscera (organs) such as stretch, pain, temperature, hunger, etc.

How well did you know this?

Not at all

Perfectly

Characteristics of special sensory

Receptors localized to small area
Hearing & balance, vision, taste, smell

How well did you know this?

Not at all

Perfectly

Motor division consists of

Somatic motor and visceral motor (autonomic)

How well did you know this?

Not at all

Perfectly

Characteristics of somatic motor

Generally voluntary
Stimulates contraction of skeletal muscles

How well did you know this?

Not at all

Perfectly

Characteristics of visceral motor (autonomic)

Generally involuntary
Stimulates contraction of smooth & cardiac muscle, secretion by glands
Includes sympathetic (fight or flight response) and parasympathetic (rest and digest)

How well did you know this?

Not at all

Perfectly

What are neurons

Excitable cells, transmit signal

How well did you know this?

Not at all

Perfectly

What are glial cells

Non-excitable, support neurons

How well did you know this?

Not at all

Perfectly

Characteristics of neurons (nerve cells)

Conduct electrical signals along plasma membrane
Extreme longevity (from fetus to elderly)
Do not divide (some CNS stem cells)
High metabolic rate (need constant supply of oxygen and glucose)

How well did you know this?

Not at all

Perfectly

Basic features of a neuron

Dendrites cell body including nucleus and nucleolus, axon hillock, and axon including Schwann cells, myelin sheath and nodes of Ranvier

How well did you know this?

Not at all

Perfectly

Neuron communcication

Neurons communicate through a synapse- pass information
Presynaptic neurons release neurotransmitters from axon
Postsynaptic neurons have neurotransmitters bind to postsynaptic membranes

How well did you know this?

Not at all

Perfectly

Structural classification types of neurons

Multipolar, unipolar (pseudounipolar), and bipolar

How well did you know this?

Not at all

Perfectly

Characteristics of multipolar neurons

Many processes extend from cell body
Many dendrites, one axon
Most abundant (99% of neurons)

How well did you know this?

Not at all

Perfectly

Characteristics of unipolar (pseudounipolar) cells

Study These Flashcards

One process from cell body that divides into 2 processes
Sensory neurons in PNS, cell bodies for ganglia
Peripheral process extends to receptors
Central process runs to the CNS

Characteristics of bipolar cells

Study These Flashcards

2 processes extend from cell body
Very rare
Some special sensory organs (inner ear, olfactory, retina)

Characteristics of sensory neurons (afferent)

Study These Flashcards

Transmit impulse toward CNS from receptors in PNS
Most are unipolar with ganglia outside CNS
Central process terminates in CNS

Characteristics of interneurons

Study These Flashcards

Between sensory and motor neurons
Multipolar within CNS
99.98% of all neurons, link together

Characteristics of motor neurons (efferent)

Study These Flashcards

Transmit impulse away from CNS
Multipolar
Cell body in CNS and form junctions with targets

Characteristics of neuroglia or glial cells

Other category of cells in nervous tissue Support neurons and cover non-synaptic parts to insulate electrical activity Six types with different functions ( 4 in CNS and 2 in PNS)

Neuroglia or glial cells in CNS

Astrocyte, microglial cells, ependymal cells, and oligodendrocytes

Neuroglia or glial cells in PNS

Satellite cells and Schwann cells

Characteristics of astrocytes

Star-shaped, most abundant Radiating ends attach to axons and capillaries (forming blood-brain-barrier) Regulate blood flow in active brain regions Regulate neurotransmitter levels

Characteristics of microglial cells

Smallest, least abundant Macrophages of CNS Engulf invading microorganisms and dead neurons

Characteristics of ependymal cells

Form epithelium that lines central cavity of spinal cord and brain (ventricles) Produces cerebrospinal fluid (CSF)

Characteristics of oligodendrocytes

Processes wrap around axons in CNS Create an insulating cover- myelin sheath

Characteristics of satellite cells

Surround neuron cell bodies within ganglia Regulate delivery of nutrients and removal of waste from neurons

Characteristics of Schwann cells (neurolemmocytes)

Myelinate axons of PNS Myelin sheaths (Schwann cells & oligodendrocytes) increase speed of impulse conduction along axon - more energy efficient Gaps between cells are nodes of Ranvier

Characteristics of gray matter

Where synapses between neurons occur Contains cell bodies of interneurons and motor neurons and short nonmyelinated interneurons

Characteristics of white matter

Contains myelinated axons (white color from myelin sheaths) and axons travel from spinal cord to brain, or brain to spinal cord Tracts- groups of axons traveling to similar destination

What is a nerve?

Rope-like organ of PNS Carry both motor and sensory axons Consists of many axons (nerve fibers in parallel bundles) Multiple layers

Layers of a nerve

Epineurium, perineurium, and endoneurium

Epineurium

Connective tissue around whole nerve

Perinuerium

Connective tissue covering bundle of nerves (fascicle)

Endoneurium

Connective tissue covering axon and Schwann cells

Characteristics of reflex arcs

Rapid, motor responses to stimuli Show most basic chain of neuronal integration Can be either somatic (skeletal muscle) or visceral (smooth or cardiac muscle, or glands) All reflex arcs have 5 components Vary in complexity based on number of synapses

Components of reflex arcs

1. Receptor 2. Sensory neuron 3. Integration center 4. Motor neuron 5. Effector

Characteristics of monosynaptic reflexes

Simplest reflex No interneurons (i.e., one synapse) Example: knee-jerk reflex

Characteristics of polysynaptic reflex

More common One or more interneurons Example: withdrawal reflex (3 neuron reflex)

Characteristics of multiple sclerosis

Autoimmune disease (not completely understood) Degeneration of myelin in CNS Disrupts neuronal signals leading to numbness or pain of skin, muscle weakness or paralysis, slurred speech, blurred vision Severity and progression varies widely with a 50% decline rapidly in second decade of disease

Characteristics of nerve regeneration

Neurons in PNS can regenerate if cell bodies survive Growth regeneration tube formed by Schwann cells release nerve growth factors (NGF) Recovery of function is possible No regeneration in the CNS as brain and spinal cord injuries result in loss of function

Functional types of neurons

Sensory neurons (afferent), interneurons, and motor neurons (efferent)

Divisions of the brain and spinal cord that represent arrangements of neurons

White and gray matter

14. Nervous Tissue Flashcards

(48 cards)