Lesson 8 - Chapter 11 (Part A: Nervous System and Tissues)
Tissue types in nervous system: What type of matter is dense collections of myelinated fibers? What type of matter is mostly neuron cell bodies and dendrites and unmyelinated fibers.
1) white matter: dense collections of myelinated fibers 2) gray matter: mostly neuron cell bodies and dendrites and unmyelinated fibers.
Short, tapering, and diffusely branched the receptive regions of the neuron convey electrical signals toward the cell body as graded potentials What part of a neuron is this?
Dendrites Note: Receive information
Line the central cavities of the brain and spinal cord and help circulate cerebrospinal fluid. Maybe ciliated (the hairs that help things move). What type of glial cell is this and what nervous system is it located in?
Ependymal cells of the CNS
ALL axons are myelinated. true or false
False. Not all are.
Astrocytes of the CNS form the _______ - _______ barrier.
Form the blood-brain barrier (control the chemical environment)
Monitor health and perform defense functions for neurons. They phagocytize microorganisms and neuronal debris. What type of glial cell is this and what nervous system is it located in?
Microglia of the CNS
have three or more processes (1 axon and several dendrites). Most abundant type. Motor neurons and interneurons are of this structural type. What structural class of neurons is this?
Multipolar neurons
There are three structural classes of neurons
Multipolar neurons, Bipolar neurons, Unipolar (pseudounipolar) neurons.
Whitish, fatty, segmented covering that protects, insulates, and increases speed of nerve impulse transmission. In the PNS, it is formed when a Schwann cells wraps many times around the axon, creating concentric layers of Schwann cell membrane. What structure of the neuron is this?
Myelin sheath
So far we have been talking about myelin sheaths in the PNS... Myelin sheaths in the CNS are formed by processes of *blank*, not the whole cell, thus there is no *blank*. Although, *blank * is present.
Myelin sheaths in the CNS are formed by processes of oligodendrocytes, not the whole cell, thus there is no neurilemma. Although, Nodes of Ranvier are present.
Neuron cell body, also called the *blank*, is the major *blank* center containing the usual organelles except for *blank*. The cell body is where the nucleus is found with *blank*.
Neuron cell body, also called the soma, is the major biosynthetic center containing the usual organelles except for centrioles . The cell body is where the nucleus is found with nucleolus. Note: Centrioles is used for cell division. Neurons cannot divide. Therefore, there is no Centrioles in the cell body of neurons.
*Blank* are specialized cells that conduct messages in the form of electrical impulses throughout the body
Neurons are specialized cells that conduct messages in the form of electrical impulses throughout the body.
Gaps in myelin sheath between adjacent Schwann cells are called *blank*. Sites where axon collaterals can emerge
Node of ranvier
Clusters of cell bodies in the CNS are called *blank*, while clusters in the PNS is called *blank*.
Nuclei in CNS Ganglia in PNS
Processes wrap CNS nerve fibers, forming insulating myelin sheaths
Oligodendrocytes of the CNS Note: This differs from the Shwann cells, because those are located in the PNS, not the CNS.
PNS is outside of the *blank*. Paired with *blank* and *blank* to carry messages from the *blank*.
PNS is outside the CNS. Paired with the brain and spinal cord to carry messages from the CNS.
MOVE ON
Review nervous system flow chart
The function is largely unknown. They are found surrounding neuron cell bodies in the PNS within ganglia. What type of glial cell is this and what nervous system is it located in?
Satellite cells of PNS
Surround peripheral nerve fibers, forming the myelin sheath. Vital to the regeneration of damaged peripheral nerve fibers. What type of glial cell is this and what nervous system is it located in?
Schwann cells (neurolemmocytes) of the PNS
The *blank* division of the peripheral nervous system carries impulses from the central nervous system to effector organs, which are *blank* and *blank*.
The motor division of the peripheral nervous system carries impulses from the central nervous system to effector organs, which are glands and muscles.
The *blank* division of the peripheral nervous system carries impulses toward the *blank* from sensory receptors located throughout the body.
The sensory division of the PNS carries impulses toward the CNS from the sensory receptors located throughout the body
Have a single short process extending from the cell body that has two branches. What structural class of neurons is this?
Unipolar (pseudounipolar) neurons
Secretory region of the neuron. It can release neurotransmitters to excite or inhibit other cells.
terminal branches
Types of neuroglia cells overview (Don't need to memorize all right now)
- astrocytes (CNS) - microglia (CNS) - Ependymal (CNS) - oligodendrocytes (CNS) - Satellite cells (PNS) - Schwann cells (PNS) We will go over each of these...
special characteristics of neurons
- extreme longevity, - amitotic (cannot divide) - high metabolic rate (need continuous supply of oxygen and glucose)
The two principal cell types of the nervous system are:
1. Neurons—excitable cells that transmit electrical signals 2. Neuroglia, or glial cells - closely associated with neurons, providing a protective and supportive network
3 overall functions of nervous system
1. Sensory input: information gathered by sensory receptors about internal and external changes 2. Integration: interpretation of sensory input 3. Motor output: activation of effector organs (muscles and glands) produces a response
The sensory division has 2 types of afferent fibers sensory. 1. *Blank* afferent fibers convey impulses from skin, skeletal, muscles, and joints 2. *Blank* afferent fibers convey impulses from visceral organs
1. Somatic afferent fibers convey impulses from skin, skeletal muscles, and joints 2. Visceral afferent fibers convey impulses from visceral organs
The motor division has is divided into 2 subdivisions... 1. The *blank* nervous system consists of *blank* nerve fibers that conduct impulses from the CNS to skeletal muscles, and allow conscious control of motor activities. 2. The *blank* nervous system is consisting of *blank* motor nerve fibers that regulate the activity of smooth muscle, cardiac muscle, and glands.
1. The somatic (voluntary) nervous system consists of somatic nerve fibers that conduct impulses from the CNS to skeletal muscles, and allow conscious control of motor activities. 2. The autonomic (involuntary) nervous system is consisting of visceral motor nerve fibers that regulate the activity of smooth muscle, cardiac muscle, and glands.
A neuron cell body has a well-developed *blank* because of the need for the production and packaging of neurotransmitters. Contains *blank*, which is a cone-shaped area on the cell body from which axon arises.
A neuron cell body has a well-developed Golgi apparatus because of the need for the production and packaging of neurotransmitters. Contains axon hillock (in the picture), which is a cone-shaped area on the cell body from which axon arises.
The PNS has two functional divisions. What are they?
A. Sensory (afferent) Division B. Motor (Efferent) Division
Regulate chemical environment of neurons and exchange between neurons and capillaries. Most abundant, versatile, highly branched glial cells. Cling to neurons, synaptic endings, and capillaries. Support and brace neurons. What type of glial cell is this and what nervous system is it located in?
Astrocytes of the CNS
Each neuron has a single *blank* that generates and conducts nerve impulses away from the cell body to the *blank* terminals, arises from the axon hillock. Can be very long.
Axon Note: Send information
Axons can branch (axon collaterals), e.g. as in a motor unit. The distal end of the axon is called the *blank*; there are numerous *blank*. This is the secretory region of the neuron. It can release neurotransmitters to excite or inhibit other cells.
Axons can branch (axon collaterals), e.g. as in a motor unit. The distal end of the axon is called the axon terminal; there are numerous terminal branches. This is the secretory region of the neuron. It can release neurotransmitters to excite or inhibit other cells.
Axons is the *blank* region of a neuron. Generates and transmits nerve impulses (action potentials) _____ from the cell body
Axons is the conducting region of a neuron. Generates and transmits nerve impulses (action potentials) away from the cell body
have a single axon and a single dendrite. rare, e.g. retinal neurons. What structural class of neurons is this?
Bipolar neurons
Bundles of processes (usually axons) are called ________ in the CNS, ________ in the PNS
Bundles of processes (usually axons) are called tracts in the CNS, nerves in the PNS
Stucture of a Neuron
Cell body, dendrites, axon
The CNS is composed of the *blank* and *blank*. It is the *blank* and *blank* center.
The CNS is composed of the brain and spinal cord. It is the integration and command center.
Unipolar neurons are typically *blank* neurons. *Blank* process - more distal branch, often associated with a sensory receptor. *Blank* process - branch entering the CNS
Unipolar neurons are typically sensory neurons. Peripheral process - a more distal branch, often associated with a sensory receptor. Central process - branch entering the CNS
The autonomic nervous system of the motor division also has 2 functional subdivisions. a) *blank*: deals with emergencies, "fight or flight" response b) *blank*: deals with "everyday" functions, "feed or breed"
a) sympathetic: deals with emergencies, "fight or flight" response b) parasympathetic: deals with "everyday" functions, "feed or breed"
There are three functional classes of neurons
a. Sensory, or afferent, neurons: transmit impulses from sensory receptors toward the CNS. b. Motor, or efferent, neurons: conduct impulses from the CNS to effectors. c. Interneurons, or association neurons: conduct impulses between sensory and motor neurons, or in CNS integration pathways. Most are entirely within the CNS.
The cytoplasm of the Schwann cell is squeezed to the periphery, forming a bulge called the
neurilemma
