anatomy lab midterm Flashcards
define homeostasis. why do we need it?
is the ability of the body to maintain a controlled
and stable internal environment by responding to internal and external stimuli. The majority
of body functions can only occur if conditions such as temperature, pH, and solute
concentrations in the body are maintained within specific physiological parameters.
what are the two divisions of the nervous system?
The cental nervous system which is made of the brain and spinal cord and the peripheral nervous system which is made of cranial and spinal nerves, ganglia and sensory receptoprs
what is a ganglion
a collection of neuronal bodies found in the voluntary and autonomic branches of the peripheral nervous system (PNS). Ganglia can be thought of as synaptic relay stations between neurons. The information enters the ganglia, excites the neuron in the ganglia and then exits.
what are neurons / nerve cells?
. The neurons or nerve cells form the functional portion of the system.
Neurons are highly specialized for impulse conduction and are responsible for all the special
attributes associated with the nervous system, such as thinking, controlling muscle activity,
and regulating glands
what are the 3 different classes of neurons
- Sensory (afferent) neurons: the neuron that conducts the impulse from the sensory
receptor to the central nervous system. - Interneuron (association neuron): integrates information from the sensory neurons
and passes the stimulus to motor neurons. - Motor (efferent) neurons: the neuron that conducts the impulse from the central
nervous system to an effector, usually a muscle or a gland.
describe dendrites
dendrites = little trees. they are the thing surrounding cell body that look like alien arms. they are the receiving or input portion of a neuron. the plasma membrane has numerous receptor sites for bringing chemical messengers from other neurons called dendritic spines
describe the cell body (also called soma)
contains a nucleus surrounded by cytoplasm that includes typical cellular organelles. also contain free ribosomes and prominent clusters of rough endoplasmic reticulum called nissl bodies
what is an axon and axon hillock
an axon is a long, thin cylindrical projection that ofen joins to the cell body at a cone-shaped elevation called the axon hillock
describe the axon collateral
along the length of an axon, side branches called axon collateral may branch off, typically at a right angle to the axon
what are axon terminals
the axon and its collaterals end by dividing into many fine processes called axon terminals
describe synaptic end bulbs/ varicositites
bulb-shaped structures. both synaptic end bulbs and varicosities contain many tiny membrane-enclosed sacs called synaptic vessels. these store neurotransmitters that excites of inhibits another neuron
what are Schwann cells
these cells encircle the entire PNS axons. They form the myelin sheath around axons. it can only myelinate a single axon and can enclose as many as 20 or more unmyelinated axons. Participate into axon regeneration
describe the myelin sheath
a multilayered lipid and protein covering around some axons that insulates them and increases the speed of nerve impulse conduction. such axons are said to be myelinated
describe the nuerolemma
The outer nucleated cytoplasmic layer of the Schwann cell, which encloses the myelin sheath, is the neurolemma . A neurolemma is found only around axons in the PNS. When an axon is injured, the neurolemma aids regeneration by forming a regeneration tube that guides and stimulates regrowth of the axon
what are myelin sheath gaps/ nodes of Rnavier
Gaps in the myelin sheath, called myelin sheath gaps, appear at intervals along the axon. Each Schwann cell wraps one axon segment between two myelin sheath gap
facilitate the rapid conduction of nerve impulses
label axon
what type of neuron is this. describe it
multipolar neurons have several dendrites and one axon and are the neuron type that
dominates the CNS.
what is the structural classification of this neuron
- Bipolar neurons have one dendrite and one axon and are found in the retina of the eye,
inner ear, and the nasal epithelium
what is the structural classification of this neuron
- Unipolar neurons have a fused axon and dendrite that emerge from the cell body as one
unit. The dendrites of these neurons form many of the other sensory receptors in the PNS
recognize slides
what is neuroglia / nueroglial cells
. Neuroglial cells
perform many different functions such as providing structural support for neurons, forming
myelin sheaths around axons, engulfing microorganisms and cell debris, and forming
cerebrospinal fluid. They also serve to prevent some substances from entering the central
nervous system.
astrocytes: PNS or CNS Functions
largest and most numerous. two types, found in grey matter and white matter. MANY FUNCTIONS! support neurons, creates blood brain barrier, regulate the growth, migration, and interconnection among neurons. during embryotic development, maintain appropriate chemical environment. may play role in memory and learning
CNS
oligodendrocytes: CNS or PNS; functions
CNS
responsible for forming and maintaining the myelin sheath around CNS axons
microglia: CNS or PNS functions
act like phagocytes. remove cellular debris formed during normal development of the nervous system and phagocytize microbes and damaged nervous tissue
CNS
ependymal cells: CNS or PNS; functions
CNS
have microvilli and cilia. Functionally, ependymal cells produce, possibly monitor, and assist in the circulation of cerebrospinal fluid. They also form the blood–cerebrospinal fluid barrier,
Schwann cells: PNS or CNS; functions
PNS
form myelin sheath around axons like oligodendrocytes. A single oligodendrocyte myelinates several axons, but each myelinates a single axon Schwann cells participate in axon regeneration, which is more easily accomplished in the PNS than in the CNS
satellite cells: PNS or CNS; function
PNS
Besides providing structural support, satellite cells (SAT-i-līt) regulate the exchanges of materials between neuronal cell bodies and interstitial fluid
functions of neurons vs neuroglia
neurons: transmit nerve impulses, and they are the only type of human cells that can carry out this function.
neuroglia: neuroglia provide support for neurons and help them carry out the basic function of nervous tissues, which is to transmit nerve impulses.
describe the structure of the spinal cord
The spinal cord is protected by the bony vertebral column and extends from the medulla
oblongata in the brain stem to the L2 vertebrae (in adults)
white matter vs gray matter
In the spinal cord, bundles of
axons that make up the white matter carry sensory information to the brain and motor
information back to the peripheral nervous system. The centrally located gray matter of the
spinal cord contains cell bodies and axons of interneurons.
what is the function of the spinal cord
The function of the spinal cord is impulse propagation from the peripheral nervous system to
the brain and from the brain to the various effectors in the body. There is also integration of
some information from sensory to motor impulses.
describe the meninges and what they do
Surrounding the spinal cord are three layers of connective tissue called spinal meninges.
These layers of connective tissue protect and cushion the spinal cord in the vertebral column
and are continuous with the cranial meninges that enclose the brain.
describe the dura mater, arachnoid mater and subdural space
The superficial layer of the spinal meninges is called the dura mater. This layer is composed
of dense irregular connective tissue and is the toughest and most protective layer of the
meninges. The middle layer is called the arachnoid mater and is composed of collagen and
elastic fibers. Between the dura mater and arachnoid mater is the subdural space which is
filled with interstitial fluid.
describe the pia mater the epidural space and the subarachnoid space
The deepest layer of the meninges adheres to the spinal cord and is called the pia mater.
This layer contains many blood vessels that nourish the tissues of the underlying spinal cord.
The epidural space is the cavity between the bone of the vertebral column and the dura
mater, and is filled with fat and other connective tissues. The space between the arachnoid
and the pia mater is called the subarachnoid space and is filled with cerebrospinal fluid.
fill in the three meninges and 3 “spaces” from deep to superficial
pia mater, subarachnoid space, arachnoid mater, subdural space, dura mater, epidural space FACT CHECK
label the spinal cord
grey mater, anterior horn and posterior horn function
grey mater conatins clusters of nerual cell bodies called nuclei, the anteror gray horn provides nerve impulses (motor)
the posterior grey horn has sensory neurons as well as cell bodies (incoming sensory info)
white matter function
coantain funiculus, carries information up and down the spinal cord. connects regions that send and receive signals
function of the spinal nerves
connects the CNS to sensory receptors
function of the central canal
encompasses an internal system of cerebrospinal fluid
what are nerve roots? what is the difference between anterior and posterior root. know what ganglia are
nerve roots are nerves that emerge from the spinal cord as 2 distinct roots
posterior root: conatina axons of sensory neurons and convcery sensory input from the receptors
anterior root: composed of axons of motor neurons and convert motor information from the CNS to the effectors to produce a response
a ganglia is a cluster of neuronal cells bodies int the PNS
anterior median fissure vs posterior median fissure. describe the filum terminale
The anterior median fissure is a wide groove on the anterior (ventral) side. The posterior median sulcus is a narrow furrow on the posterior (dorsal) side.
filum terminale (FĪ-lum ter-mi-NAL-ē = terminal filament), an extension of the pia mater that extends inferiorly, fuses with the arachnoid mater and dura mater, and anchors the spinal cord to the coccyx.