Chapter 13 Questions Based on Objectives Flashcards
The first layer of protection for the central nervous system is the_________
Hard bony skull and vertebral column.
The second protective layer of the brain is the ________
meninges
What are meninges?
three distinct protective, connective tissue coverings that encircle the spinal cord and brain.
The spinal cord is also protected by a cushion of fat and connective tissue located in the _____
epidural space
What is the epidural space?
a space between the dura mater and the wall of the vertebral canal
What are the three types of Meningeal layers?
Dura Mater
Arachnoid Mater
Pia Mater
What is Dura Mater?
The most superficial of the three spinal meninges is a thick strong layer composed of dense irregular connective tissue.
What is Arachnoid Mater?
This layer, the middle of the meningeal membranes, is a thin, avascular covering comprised of cells and thin, loosely arranged collagen and elastic fibres.
What is the subdural space?
the space between the Dura mater and Arachnoid mater, which contains interstitial fluid.
What is Pia Mater?
Innermost layer of the meninx; thin transparent connective tissue that adheres to the surface of the spinal cord and brain.
What is the Subarachnoid space?
Is the space between the Arachnoid mater and Pia mater consisting of shock-absorbing cerebrospinal fluid.
Which of the three mater layers contains blood vessels that supply oxygen and nutrients to the spinal cord?
Pia Mater
In External Anatomy of the Spinal Cord What is Cervical enlargement?
Enlargements extending from the 4th cervical vertebra (C4) to the 1st thoracic vertebra (T1).
What nerves are in the Cervical Enlargement?
Nerves to and from the upper limbs are from the cervical enlargement.
In External Anatomy of the Spinal Cord, What is Lumbar enlargement?
Inferior enlargement, extends from the 9th (T9) to twelfth (12th) thoracic vertebra.
What nerves are in the Lumbar Enlargement?
Nerves to and from the lower limbs are from the lumbar enlargement
In External Anatomy of the Spinal Cord, What is Conus medullaris?
Inferior to cervical and lumbar enlargement, the spinal cord terminates as a conical structure called conus medullaris.
In External Anatomy of the Spinal Cord, What is Filum Terminal?
Extension of pia mater that extends inferiorly (down) fuses with arachnoid mater and dura mater. And anchors the spinal cord to the coccyx.
In External Anatomy of the Spinal Cord, What is Cauda equina?
The roots of nerves are collectively called Cauda equina (horse’s tail).
In Internal Anatomy of the Spinal Cord, What is Anterior median fissure?
Wide groove on the anterior side, penetrating the white matter.
In Internal Anatomy of the Spinal Cord, What is Posterior median sulcus?
Narrow furrow on the posterior side, penetrating the white matter.
In Internal Anatomy of the Spinal Cord, What is Gray commissure?
Forms the crossbar of the H (grey matter).
In Internal Anatomy of the Spinal Cord, What is the Central canal?
Small space in the center of the Gray commissure.
-Extends the length of the spinal cord filled with cerebrospinal fluid.
In Internal Anatomy of the Spinal Cord, What is
Anterior or White commissure?
Anterior to gray commissure; connects the white matter of the left and right sides of the spinal cord.
In Internal Anatomy of the Spinal Cord, What are Nuclei?
Clusters of cell bodies form functional groups.
What do Sensory nuclei do?
Receive input from sensory neurons, and motor nuclei provide output via motor neurons.
In Internal Anatomy of the Spinal Cord, What is
Posterior (dorsal) gray horns?
Contain cell bodies and axons of interneurons as well as axons of incoming sensory neurons.
In Internal Anatomy of the Spinal Cord, What is Anterior (ventral) gray horns?
Contain somatic motor nuclei which provide nerve impulses for contraction of skeletal muscles.
In Internal Anatomy of the Spinal Cord, What is Lateral gray horns?
Between posterior and anterior gray horns; present only in thoracic and upper lumbar segments.
What do Lateral gray horns contain?
autonomic motor nuclei
What do autonomic motor nuclei do?
It regulates the activity of cardiac muscles, smooth muscles, and glands.
The white matter of the spinal cord is organized into 3 regions called?
Funiculi of Columns
What are the three regions of the spinal cord’s white matter?
(1) anterior white funiculi
(2) posterior white funiculi
(3) lateral white funiculi
Each funiculus, in turn, contains distinct bundles of axons having a funiculus origin or destination and carrying similar information. What are these bundles called?
Tracts
Recall that tracts are bundles of axons in the ______, whereas nerves are bundles of axons in the ______
CNS
&
PNS
_________tracts consist of axons that conduct nerve impulses toward the brain.
Sensory (ascending)
Tracts consisting of axons that carry nerve impulses from the brain are called ____________tracts
motor (descending)
How the Spinal Nerve is connected to the Spinal Cord. Define Roots
Two bundles of axons connect each spinal nerve to a segment of the cord.
How the Spinal Nerve is connected to the Spinal Cord. Define Rootlets
are smaller bundles of axons that connects the roots to the cord.
How the Spinal Nerve is connected to the Spinal Cord. Define Posterior (dorsal) root
Contain sensory axons which conduct nerve impulses from skin, muscles, and internal organs to the CNS.
How the Spinal Nerve is connected to the Spinal Cord. Define Posterior (dorsal) root ganglion
A swelling of the posterior root containing cell bodies of sensory neurons.
How the Spinal Nerve is connected to the Spinal Cord. Define Anterior (ventral) root
Contains axons of motor neurons, conduct nerve impulses from CNS to effectors.
What are Spinal Nerves?
Parallel bundles of axons and their associated neurological cells wrapped in several layers of connective tissue.
How do spinal nerves connect to the spinal cord?
It has two connections to the cord: posterior and anterior root
The posterior and anterior roots unite to form a spinal nerve at the _____________ ______________
intervertebral foramen.
Because the posterior root contains sensory axons and the anterior root contains motor axons, a spinal nerve is classified as a ______
mixed nerve
The ______________ root contains a spinal ganglion in which cell bodies of sensory neurons are located.
Posterior
How are the spinal nerves named and numbered?
The 31 pairs of spinal nerves are named and numbered according to the region and level of the vertebral column from which they emerge.
Individual axons within a nerve, whether myelinated or unmyelinated, are wrapped in _______
endoneurium, the innermost layer
What are individual axons within a nerve wrapped in?
endoneurium
What makes up endoneurium?
A mesh of collagen fibres, fibroblasts, and macrophages.
Groups of axons with their endoneurium are held together in bundles called _______
nerve fascicles
What are nerve fascicles wrapped in?
perineurium
The perineurium is a thicker layer of what type of tissue?
Connective tissue.
The outermost covering over the entire nerve is the ________
epineurium
What makes up the epineurium?
fibroblasts and thick collagen fibers.
What is a branch of spinal nerves?
After passing through its intervertebral foramen a short distance, a spinal nerve divides into several branches.
What are the branches of the spinal nerves called?
These branches are known as rami
What branch of the spinal nerves serves the deep muscles and skin of the posterior surface of the trunk?
The posterior (dorsal) ramus
What branch of the spinal nerves serves the muscles and structures of the upper and lower limbs and the skin of the lateral and anterior surfaces of the trunk?
The anterior (ventral) ramus
In addition to posterior and anterior rami, spinal nerves also give off a ________ _________
meningeal branch
What spinal branch reenters the vertebral cavity through the intervertebral foramen and supplies the vertebrae, vertebral ligaments, blood vessels of the spinal cord, and meninges
meningeal branch
Other branches of a spinal nerve are the ________ ______ which are components of the autonomic nervous system
communicating rami
What is a plexus?
Network of axons that do not go directly to the body structures they supply (supply of nerves).
The principal plexuses are? There are 5
cervical plexus
brachial plexus
lumbar plexus
sacral plexus
smaller coccygeal plexus
What is a Cervical plexus?
Supply the skin and muscles of the head, neck, and superior parts of shoulders and chest.
What does a Brachial plexus do?
Provides nerve supply of shoulders and upper limbs.
What does a Lumbar plexus do?
Supplies nerves to the anterolateral abdominal wall, external genitals, and part of the lower limb.
What does a sacral plexus do?
Supplies nerves to the buttocks, perineum, and lower limbs.
What does a coccygeal plexus do?
Supplies a small area of skin in the coccygeal region.
What are intercostal nerves?
Nerves from T2–T12 do not enter into the formation of plexuses and are known as intercostal nerves
What are Dermatomes?
Area of skin that provides sensory input to the CNS via a pair of spinal nerves.
Which is the only spinal nerve that does not have a corresponding dermatome?
C1 spinal nerve
Knowing which spinal cord segments supply each ___________makes it possible to locate damaged regions of the spinal cord
dermatome
Name the superficial sensory branches of the cervical plexus. there are 4
Lesser occipital
Great auricular
Transverse cervical
Supraclavicular
Name the deep large motor branches of the cervical plexus. there are 5
Ansa cervicalis
Superior root
Inferior root
Phrenic
Segmental branches
What is the origin and description of the Lesser Occipital
Origin: C2
Description: Skin of scalp posterior and superior to ear.
What are the origin and description of the Great auricular?
Origin: C2–C3
Description: Skin anterior, inferior, over-ear, and over-parotid glands.
What are the origin and description of the Transverse cervical?
Origin: C2-C3
Description: Skin over the anterior and lateral aspect of the neck.
What are the origin and description of the Supraclavicular?
Origin: C3-C4
Description: Skin over the superior portion of the chest and shoulder.
What is the origin and description of the Ansa cervicalis
Origin:
Description: Divides into superior and inferior roots.
What is the origin and description of the Superior root
Origin: C1
Description: Infrahyoid and geniohyoid muscles of the neck.
What is the origin and description of the Inferior root
Origin: C2-C3
Description: Infrahyoid muscles of the neck.
What are the origin and description of the Phrenic?
Origin: C3-C5
Description: Diaphragm.
What are the origin and description of the Segmental branches?
Origin: C1-C5
Description: Prevertebral (deep) muscles of the neck, levator scapulae, and scalenus medius muscles.
The roots (anterior rami) of spinal nerves C5–C8 and T1 form the _______
brachial plexus
Where does the brachial plexus extend?
extends inferiorly and laterally on either side of the last four cervical and first thoracic vertebrae
Where are the brachial plexus roots?
anterior rami of the spinal nerves
The roots of several spinal nerves unite to form trunks in the inferior part of the neck. In what plexus
Brachial Plexus
The branches of the brachial plexus form?
The principal nerves of the brachial plexus.
What are the Five large terminal branches that arise from the brachial plexus?
The axillary nerve
The musculocutaneous nerve
The radial nerve.
The median nerve
The ulnar nerve
Where does the axillary nerve in the brachial plexus supply nerves to?
supplies the deltoid and teres minor muscles
Where does the musculocutaneous nerve in the brachial plexus supply nerves to?
supplies the anterior muscles of the arm
Where does the radial nerve in the brachial plexus supply nerves to?
supplies the muscles on the posterior aspect of the arm and forearm
Where does the median nerve in the brachial plexus supply nerves to?
supplies most of the muscles of the anterior forearm and some of the muscles of the hand
Where does the ulnar nerve in the brachial plexus supply nerves to?
supplies the anteromedial muscles of the forearm and most of the muscles of the hand.
What forms the lumbar plexus?
The roots (anterior rami) of spinal nerves L1–L4
What nerve supplies the Muscles of the anterolateral abdominal wall, skin of the inferior abdomen and buttocks?
Where is this nerve found?
Iliohypogastric
and
L1
What nerve supplies the Muscles of the anterolateral abdominal wall, skin of the superior and medial aspect of the thigh, the root of the penis and scrotum in males, and labia majora and mons pubis in females.
Where is this nerve found?
Ilioinguinal
and
L1
What nerve supplies Cremaster muscle; the skin over the middle anterior surface of the thigh, scrotum in males, and labia majora in females.
Where is this nerve found?
Genitofemoral
&
L1–L2
What nerve supplies Skin over lateral, anterior, and posterior aspects of the thigh?
Where is this nerve found?
Lateral femoral cutaneous nerve
&
L2–L3
What nerve supplies the Largest nerve arising from the lumbar plexus, distributed to flexor muscles of the hip joint and extensor muscles of the knee joint, skin over the anterior and medial aspect of the thigh and medial side of the leg and foot?
Where is this nerve found?
Femoral
&
L2–L4
What nerve supplies the Adductor muscles of the hip joint; the skin over the medial aspect of the thigh?
Where is this nerve found?
Obturator
&
L2–L4
The roots (anterior rami) of spinal nerves L4–L5 and S1–S4 form the __________ plexus
Sacral Plexus
The _________supplies the buttocks, perineum, and lower limbs.
Sacral Plexus
The largest nerve in the body—the ______ nerve—arises from the sacral plexus.
sciatic
The roots (anterior rami) of spinal nerves S4–S5 and the coccygeal nerves form a small _________plexus
coccygeal plexus
From what plexus arises the anococcygeal nerves, which supply a small area of skin in the coccygeal region.
coccygeal plexus
What nerve supplies the Gluteus minimus, gluteus medius, and tensor fasciae latae muscles?
Where is this nerve found?
Superior gluteal
&
L4–L5 and S1
What nerve supplies the Gluteus maximus muscle?
Where is this nerve found?
Inferior gluteal
L5–S2
What nerve supplies the Piriformis muscle?
Where is this nerve found?
Nerve to piriformis
S1–S2
What nerve supplies the Quadratus femoris and inferior gemellus muscles?
Where is this nerve found?
Nerve to quadratus femoris and inferior gemellus
L4–L5 and S1
What nerve supplies the Obturator internus and superior gemellus muscles?
Where is this nerve found?
Nerve to obturator internus and superior gemellus
L5–S2
What nerve supplies Skin over the inferior medial aspect of the buttocks?
Where is this nerve found?
Perforating cutaneous (kū′-TĀ-nē-us)
S2–S3
What nerve supplies Skin over the anal region, inferior lateral aspect of buttocks, superior posterior aspect of the thigh, superior part of the calf, scrotum in males, and labia majora in females.
Where is this nerve found?
Posterior femoral cutaneous nerve
S1–S3
What nerve supplies Muscles of the perineum, the skin of the penis and scrotum in males and clitoris, labia majora, labia minora, and vagina in females.
Where is this nerve found?
Pudendal
S2–S4
What nerve supplies Actually two nerves—tibial and common fibular—bound together by common sheath of connective tissue; splits into its two divisions, usually at the knee. (See below for distributions.) As sciatic nerve descends through thigh, it sends branches to hamstring muscles and adductor magnus.
Where is this nerve found?
Sciatic (sī-AT-ik)
L4–S3
What nerve supplies Gastrocnemius, plantaris, soleus, popliteus, tibialis posterior, flexor digitorum longus, and flexor hallucis longus muscles. Branches of tibial nerve in foot are medial plantar nerve and lateral plantar nerve.
Where is this nerve found?
Tibial
L4–S3
What nerve supplies Abductor hallucis, flexor digitorum brevis, and flexor hallucis brevis muscles, the skin over the medial two-thirds of the plantar surface of the foot?
Medial plantar
What nerve supplies the Remaining muscles of the foot not supplied by the medial plantar nerve, skin over the lateral third of the plantar surface of the foot?
Lateral plantar
What nerve supplies Divides into superficial fibular and deep fibular branches.
Where is this nerve found?
Common fibular
L4–S2
What nerve supplies Fibularis longus and fibularis brevis muscles; the skin over the distal third of the anterior aspect of the leg and dorsum of the foot.
Superficial fibular
What nerve supplies Tibialis anterior, extensor hallucis longus, fibularis tertius, extensor digitorum longus and extensor digitorum brevis muscles; skin on adjacent sides of great and second toes.
Deep fibular
What is the Spinothalamic tract?
Conveys nerve impulses for sensing pain, warmth, coolness, itching, tickling, deep pressure, and crude touch.
What are the Direct motor pathways?
Convey nerve impulses originating from the cerebral cortex and cause voluntary movements of skeletal muscles.
What are the Indirect motor pathways?
Convey nerve impulses from the brain stem to cause automatic movements and help coordinate body movements with visual stimuli.
What is a Reflex?
Fast, involuntary, unplanned sequence of actions that occur due to a particular stimulus.
What is a Spinal reflex?
Integration occurs at the spinal cord grey matter i.e. knee jerk.
What is a Cranial reflex?
Integration occurs at the brain stem, i.e. tracking the movement of eyes while reading.
What is a Somatic reflex?
Contraction of skeletal muscles.
What is an Autonomic (visceral) reflex?
Response of smooth muscles, cardiac muscle, and glands
What is a reflex arc?
The pathway an impulse follow to produce a reflex.
What are the 5 functional components of a reflex arc?
1.Sensory Receptor
2. Sensory Neuron
3. Integrating center
4. Motor Neuron
5. Effector
In the function of a reflex arc, what does a sensory receptor do?
Dendrites respond to specific stimuli by producing a graded potential called a generator (receptor) potential. It must reach the threshold.
In the function of a reflex arc, what does a Sensory Neuron do?
Impulse propagate from sensory receptor to axon terminals in the gray matter of spinal cord or brain stem. Relay neurons send nerve impulses to brain.
In the function of a reflex arc, what are the 2 parts of the Integrating center
o Monosynaptic reflex arc
o Polysynaptic reflex arc
What is the Monosynaptic reflex arc?
is a pathway with one synapse in the CNS.
What is the Polysynaptic reflex arc?
involves two types of neurons and more than one CNS synapse
In the function of a reflex arc, what does a Motor Neuron do?
Impulses propagate out of CNS to a motor neuron or part of the body.
In the function of a reflex arc, what does the Effector do?
Part of the body that responds to the motor nerve impulse.
