Term 3 Chapter 16 Nervous Tissue Flashcards
Which two systems are the body’s major control centres?
The Nervous system and Endocrine system
What does the nervous system consist of?
- Brain and cranial nerves (and their branches)
- Spinal cord and spinal nerves (and their branches)
- Ganglia, enteric plexuses and sensory receptors
The Central nervous includes ?
Brain and Spinal cord

What does the Peripheral Nervous system (PNS) include? (4)
- nerve
- ganglia
- enteric plexuses
- sensory receptors

Define nerve
Bundle of axons with connective tissue and blood cells that are located outside the brain and spinal cord
Define ganglia
Small masses of nerve tissue located outside the brain and spinal cord
What are enteric plexuses?
Neuronal network located in the walls of the GI tract organs that help regulate digestive system activities
What are sensory receptors?
Part of the Peripheral nervous system.
- Specialized nerve endings that monitor changes in the internal and external environments
What are the two major divisions of the nervous system and what do they consist of?
- Central Nervous System
- Brain
- Spinal Cord
- Peripheral Nervous System
- All nerve structures outside of the CNS
- Includes sensory and motor neurons
- Cranial nerves that emerge from the brain (I-XII)
- Spinal nerves that emerge from the spinal cord (32 pairs)
What is the function of sensory (afferent) neurons?
Transmit nerve impulses from sensory receptors to the CNS
*Afferent = Arrival at CNS*
What is the function of Motor (Efferent) neurons?
Transmit nerve impulses from the CNS to muscles and glands
*Efferent = Exits CNS
What are two functions of the sensory function of the nervous system?
- Detect stimuli in the internal and external environments
- Transmit information by sensory/afferent neurons to the brain or spinal cord
What is the integrative function of the Nervous system? (Involves interneurons)
Play a role in analyzing the sensory information to
- provide perception,
- store some of it, and
- make decisions regarding appropriate behaviours
What is the Motor function of the nervous system? (includes motor/efferent neurons)
Respond to integration decisions by initiating actions in effectors (muscle fibers and glandular cells)
The image shows a reflex circuit in which interneurons affect motor response without the signal going to the brain.
Label the neurons


What are the two divisions of the Peripheral Nervous System?
- Somatic Nervous System
- Autonomic Nervous system
What two types of neurons make up the Somatic Nervous System?
- Somatic Sensory Neurons
- Somatic Motor Neurons
What is the function of somatic sensory neurons?
Convey information to the CNS from sensory receptors in the skin, skeletal muscles, and joints, and from the receptors for the special senses (vision, hearing, equilibrium, taste, smell)
What is the function of Somatic Motor Neurons?
Neurons that convey information from the CNS to skeletal muscles only
The somatic sensory pathways are involved in the ____ of information to the ___ for integration (processing)
The somatic sensory pathways are involved in the input of information to the CNS for integration (processing)
The Somatic motor pathways are involved in the ______ of information from the ____ that results in _____ ______. Is this voluntary or involuntary?
The Somatic motor pathways are involved in the output of information from the CNS that results in muscular contraction. Voluntary
The autonomic nervous system is the second division of the PNS. What two types of neurons make up the ANS?
- Autonomic (visceral) sensory neurons
- Autonomic Motor Neurons
What is the function of Autonomic sensory neurons?
Convey information to the CNS form autonomic sensory receptors, located primarily in the visceral* organs
*smooth muscle organs in the thorax abdomen and pelvis
What is the function of Autonomic Motor Neurons
convey information from the CNS to smooth muscle and cardiac muscle and glands that cause the muscles to contract and the glands to secrete
*Involuntary action
The ANS is further split into three divisions, what are they?
- Sympathetic Division
- Parasympathetic Division
- Enteric Nervous system
The parasympathetic nervous system is a major regulator of what?
the smooth muscle of the digestive and respiratory system
The sympathetic nervous system is more widely distributed than the parasympathetic nervous system because it is the major regulator of?
Smooth muscle of the cardiovascular system (blood vessels are located everywhere in body = greater distribution)
The enteric nervous system (termed the “brain of the gut”) consists of over 100 million neurons that occur throughout the length of the _______
Gastrointestinal (GI) tract
Like the SNS and ANS, the ENS also has both sensory and motor components. However, while they can operate independently, they can ______ and are _______ by _______
Like the SNS and ANS, the ENS also has both sensory and motor components. However, while they can operate independently, they can communicate and are regulated by other branches of the ANS
Sensory neurons of the ENS have what function?
Monitor chemical changes within the GI tract as well as the stretching of its walls
What is the function of the motor neurons of the ENS?
Govern contraction of GI tract smooth muscle to propel food through the GI tract
Also control secretions of the GI tract organs (such as acid from the stomach) and endocrine cells (secrete hormones).
Is the ENS involuntary or voluntary?
Involuntary. ALL divisions of the ANS are involuntary
What is the main difference between motor neurons and sensory neurons?
Motor neurons cause muscles to contract while sensory neurons allow us to feel sensations
Label the motor neuron


What is nervous tissue? What are two types of cells in nervous tissue?
vascular tissue comprised of two types of cells: Neurons and neuroglia
Neurons are highly specialized cells that cannot undergo ______
mitosis
What are neuroglia in comparison to neurons?
What are 2 functions?
What is an important difference from neurons?
- Small and more abundant than neurons
- Functions:
- Support and nourish neurons
- Protect neurons by maintaining interstitial fluid around them
- Retains ability to divide (undergo mitosis)
Label the parts of a neuron


What are nissl bodies (of neurons)
Ribosomes - responsible for protein synthesis
What part of an axon helps maintain neuron cell shape?
Neurofibril (cytoskeleton)
Neurons have a projection that joins the axon to the cell body. What is the name of this projection and what is significant about it?
Axon hillock
Origin site of the action potential
Aging neurons contain yellow brown pigments called ?
Lipofuscin
Label the features of the axon:
Axoplasm and Axolemma.
What is axoplasm?
What is Axolemma?

Axoplasm: cytoplasm of an axon
Axolemma: the plasma membrane of an axon

_____ are the receiving/input portion of a neuron
(usually short and highly branched)
Dendrites
______, found in the plasma membrane, increase surface area for receptors of a neuron.
Dendritic gemmules (spines)
The _____ of a neuron carries nerve impulses away from the cell body toward an effector.
Provide three examples of an effector.
Axon
Effectors include: Another neuron, muscle or gland
Label the parts of a synapse

What is a synapse?
A synapse is the site of communication between the transmitting neuron and a signal recipient (another neuron, gland or muscle)

Label the diagram.
Define:
Presynaptic Neuron
Postsynaptic Neuron

Presynaptic Neuron: neuron that lies before the synapse; carries a nerve impulse toward a synapse
Postsynaptic Neuron: Neuron that lies after the synapse; carries a nerve impulse away from a synapse

What is a neuromuscular junction and what occurs there?
Synapses between a neuron and a muscle fibre
- Synaptic vesicles release the Neurotransmitter acetylcholine (ACh), which induces muscle contraction
What is a neuroglandular junction?
Synapses between a neuron and a gland cell
How are neurons classified?
Based on structure and funtionality
What are the three types of neuron?
- Multipolar Neurons: several dendrites and one axon
- Bipolar Neurons: One main dendrite and One axon
- Unipolar Neurons: sensory neurons that have only one process

Dendritic branching is often distinctive to a particular type of neuron.
For example: Which of the images shows a purkinje cell and which shows a pyramidal cell?
Where would you find each of these types of cell?

Purkinje cells in the cerebellum
Pyramidal cells in the cerebral cortex of the brain

What are the 6 types of neuroglia?
Four found only in the CNS:
- Astrocytes
- oligodendrocytes
- microglia
- ependymal cells
Two present in PNS:
- Schwann cells (neurolemmocytes)
- Satellite cells
Label the 5 types of neuroglial cells in the CNS


Protoplasmic astrocytes are located in _______ matter while fibrous astrocytes are located mainly in ______ matter
Protoplasmic astrocytes are located in grey matter while fibrous astrocytes are located mainly in white matter
What are five functions of astrocytes?
- Cell microfilaments provide strength and support neurons
- astrocyte processes wrap around capillaries and regulate permeability of the capillary endothelium (blood brain barrier)
- regulate growth, migration and interconnections among neurons in the brain of developing embryos
- maintain appropriate environment for generating nerve impulses
- probable role in learning and memory by influencing formation of neural synapses
Oligodendrocytes have process that forms the ______ (____ + ______) covering around some axons
Oligodendrocytes have process that forms the myelin sheath (lipid + protein) covering around some axons
Microglia originate in the ______ and migrate to the _____ as it develops. And functions as a _______ to remove cellular debris, invading microbes and damaged tissue
Microglia originate in the red bone marrow and migrate to the CNS as it develops. And functions as a phagocyte to remove cellular debris, invading microbes and damaged tissue
Cells that line the ventricles of the brain and central canal of the spinal cord are_____, which produce _____ as well as form the _________.
Cells that line the ventricles of the brain and central canal of the spinal cord are Ependymal Cells, which produce Cerebrospinal fluid (CSF) as well as form the blood-cerebrospinal fluid barrier.
Schwann cells have two main functions:
- encircle PNS axons and form the myelin sheath
- Participate in axon regeneration of severed axons
What do satellite cells do? Where are they found?
Satellite cells surround the cell bodies of neurons of the PNS ganglia
Cells regulate the exchange of materials between neuronal cell bodies and interstitial fluid
Label the types of neural circuits depicted

