Chapter 16: Spinal Cord and Spinal Nerves Flashcards
The spinal cord is known as what center due to sensory input and motor output?
Reflex center
Label the parts of the spinal cord.
- T12-L1: Conus medullaris
- terminal spinal cord at L1
- stops at age 4 - Nerve cord: Cauda equina
- horse tail - Coccyx1: Filum teriminale
Label the spinal cord meninges.
- Epidural space (real)
- Dura mater
- Subdural space (potential space)
- Arachnoid mater
- Subarachnoid space (CSF)
- Pia mater
T/F. On the sectional anatomy of the spinal cord, the posterior refers to the sensory and anterior refers to motor.
True
Identify the white matter and gray matter structures.
White matter
1. Posterior funiculus
2. Lateral funiculus
3. White commissure
4. Anterior funiculus
Gray matter
1. Posterior horn
2. Gray commissure
3. Lateral horn
4. Anterior horn
The posterior horn contains:
- axons of sensory neurons
- cell bodies of interneurons
Describe the 2 sensory receptors of the posterior horn.
- Somatic sensory receptor: pain, pressure receptors on skin
- Visceral sensory receptor: stretch in smooth muscle from viscera
What is contained in the posterior root ganglion?
A. cell bodies of sensory neurons
B. cerebral spinal fluid
C. cell bodies of motor neurons
A. cell bodies of sensory neurons
The anterior horn contains:
- cell bodies of somatic motor neurons that innervate skeletal muscle
The lateral horn contains:
- cell bodies of autonomic neurons that innervate smooth muscle, cardiac muscle, and glands
Categorize the spinal nerves based on location and include the number.
Cervical part:
C1-C8
Thoracic part:
T1-T12
Lumbar part:
L1-L5
Sacral part:
S1-S5
Coccyx part:
Co1-Co4
Distinguish the sensory receptor and the effectors from the image.
Posterior (blue) = sensory
- receptors
Anterior (red) = motor/effector
- muscle
Posterior + Anterior roots merge but spinal nerve ….
Splits
The cervical plexus innervates the muscles of the:
A. head
B. neck
C. sacrum
D. thoracic cavity
B. neck
The brachial plexus supplies:
The upper limbs
List the 5 major terminal branches of the brachial plexus that innervates the arm.
- Axillary nerve
- Musculocutaneous nerve
- Radial nerve
- Median nerve
- Ulnar nerve
Axillary nerve motor innervation and cutaneous innervation is?
Motor: deltoid, teres minor
Cutaneous: superolateral arm
Median nerve motor innervation and cutaneous innervation is?
Motor: Anterior forearm muscles, thumb muscles, lateral lumbricals
Cutaneous: dorsal tips
Musclulocutaneous nerve motor innervation and cutaneous innervation is?
Motor: Anterior arm muscles
Cutaneous: lateral region of forearm
Radial nerve motor innervation and cutaneous innervation is?
Motor: Posterior arm and forearm muscles
Cutaneous: lateral 3 digits, posterior region of arm and forearm
Ulnar nerve motor innervation and cutaneous innervation is?
Motor: Anterior forearm muscles, hand muscles
Cutaneous: medial 1 1/2 digits
Do the intercostal nerves have a thoracic plexus?
No
The lumbar plexus innervates….
- abdomen
- external genitalia
- anterior and medial thigh
The sacral plexus innervates….
- pelvis
- posterior thigh
- leg
- foot
The main nerve in the sacral plexus is which nerve?
Sciatic nerve (longest in the body)
List 5 characteristics of reflexes.
- stimulus
- rapid response
- automatic response
- involuntary response
Describe the 5 steps of the reflex arc in order.
- Receptor responds
- Sensory neuron to spinal cord (posterior)
- Integration (sometimes by interneuron)
- Motor neuron to effector (anterior)
- Effector responds (muscle)
Classify the following reflex:
Receptor and effector on the same side.
Ispilateral
Classify the following reflex:
Sensory from receptor cross over through spinal chord to activate effector on opposite limb
Contralateral
Classify the following reflex:
Sensory axons to motor neurons (knee-jerk)
Monosynaptic
Classify the following reflex:
Involve interneurons (withdrawl reflex)
Polysynapl
Describe what nerve could be damaged due to the following injuries:
- compressed axilla
- neck of humerus broken
Axillary nerve
Describe what nerve could be damaged due to the following injuries:
- humeral shaft fracture/elbow
- paralysis of extensor muscles of arm
- anesthesia along posterior arm
Radial nerve
Describe what cord could be damaged due to the following injuries:
- improper use of crutches
Posterior cord (axillary and radial nerve)
Describe what nerve could be damaged due to the following injuries:
- carpal tunnel syndrome
- paralysis of lateral lumbricals
- anesthesia in part of hand
- Median
Describe what nerve could be damaged due to the following injuries:
- fractures/dislocation of elbow
- paralysis of intrinsic hand muscles
Ulnar
Describe what trunk could be damaged due to the following injuries:
- excessive separation of neck and shoulder
- any brachial plexus branch
Superior trunk (C5-C6)
Describe what nerve could be damaged due to the following injuries:
- arm excessively abducted
- any brachial plexus branch
Inferior trunk (C8-T1)
The phrenic nerve innervates ….
The diaphragm
