SCB 204 - Lecture Quiz 2

Lectures 5-9 Objective Questions + More

What does the spinal cord form?

Inferior part of the CNS

What are the features of the spinal cord?

• Long tubular organ within the vertebral cavity
• Passes through the foramen magnum and joins the brainstem

What is the function of the spinal cord?

To relay and process information through stations

What is the spinal relay station?

• Intermediate between body and brain
• Receives outgoing information from the brain and sends it to the body
• Receives incoming information from the body and sends it to the brain

What is the spinal processing station?

• Performs some integration and processing

• Spinal reflexes can be carried out by the spinal cord alone

What kind of matter does the spinal cord contain?

Gray and white

What protects the spinal cord?

Spinal meninges

Which layer does the spinal dura mater lack?

Periosteal

How does the spinal pia mater anchor the spinal cord in the vertebral cavity?

Denticulate ligaments

Which space in the spinal meninges is the site for a lumbar puncture or spinal tap to remove CSF?

Subarachnoid

Where does the spinal cord extend from?

Foramen magnum to between the L1 and L2 vertebrae

Fill in the blank: The spinal cord has a narrower _

Posterior median sulcus

Fill in the blank: The spinal cord has a wider _

Anterior median fissure

What does the end of the spinal cord form?

Conus medullaris

What does the spinal pia mater form at L1 and L2?

Filum terminale

What is the structure of spinal nerves?

Originate from the spinal cord and innervate below the head and neck

Which nerve roots project from each side of the spinal cord to form spinal nerves?

Posterior (sensory) and anterior (motor)

What carries sensory and motor impulses to and from the spinal cord?

Spinal nerves

What contains cell bodies of sensory neurons?

Posterior root ganglion

What connective tissue sheath holds spinal nerves together?

Epineurium

What is inside spinal nerves?

Nerve axons bundled together as fascicles surrounded by a perineurium

What is each spinal nerve axon within a fascicle surrounded by?

Endoneurium

What are nerve plexuses?

Networks formed from spinal nerves

What are the principal nerve plexuses?

• Cervical (C1-C5)
• Brachial (C5-T1)
• Lumbar (L1-L4)
• Sacral (L4-S4)

What structures does the axillary nerve innervate?

• Motor to the deltoid and teres minor muscles
• Sensory to the skin over the deltoid

What structures does the radial nerve innervate?

• Motor to the triceps brachii, brachioradialis, and the extensor muscles of the forearm and digits
• Sensory to the posterior arm and forearm, posterior thumb, and posterior second, third, and lateral half of the fourth digits

What structures does the musculocutaneus nerve innervate?

• Motor to the biceps brachii, coracobrachialis, and brachialis muscles
• Sensory to the lateral forearm

What structures does the median nerve innervate?

• Motor to most of the muscles that flex the wrist and digits and certain muscles of the hand
• Sensory to the anterior thumb and the anterior second, third, and lateral side of the fourth digits

What structures does the ulnar nerve innervate?

• Motor to certain forearm flexors and most of the intrinsic hand muscles
• Sensory to the fifth digit and the median half of the fourth digit

Define dermatomes

A segmentation of skin based on the innervation of spinal nerves

What is the anatomy of the internal spinal cord?

Butterfly-shaped spinal gray matter surrounded by spinal white matter

What is the central canal (of spinal gray matter)?

A CSF-filled canal which runs down the middle of the spinal cord

What connects the butterfly wings (of spinal gray matter) of the spinal cord?

Gray commissure

What is the anterior horn (of spinal gray matter) associated with?

Somatic motor functions

What is the posterior horn (of spinal gray matter) associated with?

Somatic and visceral sensory information

What is the lateral horn (of spinal gray matter)?

• Present from the first thoracic vertebrae to lumbar
• Contains cell bodies for the motor control of viscera via the ANS

What is the function of spinal white matter?

Relay station

What does spinal white matter contain?

Axons of neurons that travel to and from the brain

What is each region of the spinal white matter?

Funiculi organized into tracts or columns that ascend (sensory) or descend (motor) the spinal cord

What is a reflex?

A protective programmed automatic response to stimuli

What are the parts of a reflex arc?

1. Sensory (PNS afferent) division
2. CNS neural integration
3. Motor (PNS efferent) division

What is the function of the sensory (PNS afferent) division (part 1) of a reflex arc?

PNS detects and delivers the stimulus to the CNS

What is the function of CNS neural integration (part 2) in a reflex arc?

Integrates the stimulus

What is the function of the motor (PNS efferent) division (part 3) of a reflex arc?

PNS delivers motor response from the CNS to effectors

How are reflexes classified?

By the number of synapses and type of organs

How many synapses do monosynaptic reflexes contain?

1

How many synapses do polysynaptic reflexes have?

Multiple

Which type of reflex is a simple stretch reflex?

Monosynaptic

Which type of reflex is the patellar/knee jerk reflex?

Monosynaptic simple stretch reflex

How is the patellar/knee jerk reflex produced?

Tapping the patellar tendon with a reflex hammer

What is the function of the polysynaptic golgi tendon reflex?

Protects muscles and tendons from damage

What does the polysynaptic golgi tendon reflex cause?

Muscle relaxation

Which other reflex does the crossed extension reflex occur simultaneously with?

Flexion

What does contralateral refer to?

Opposite side of the body

What does ipsilateral refer to?

Same side of the body

What is reciprocal inhibition?

Relaxation of a muscle on one side of a joint to accommodate the contraction of a muscle on the other side

What neurons does a somatic reflex involve?

Somatic sensory and motor

Where do visceral reflexes innervate?

Internal organs

Which reflex is associated with the ANS?

Visceral

What is the location and function of the brain?

Located in the cranial cavity and controls most bodily functions

What are the major parts of the brain?

• Cerebrum
• Diencephalon
• Cerebellum
• Brain stem

What are the functions of the cerebrum?

• Higher mental functions
• Interpretation of sensory stimuli (sensation)
• Planning and initiating movement
• Learning, memory, personality, cognition, language and conscience

What is the diencephalon?

Central core beneath cerebral hemispheres

What are the functions of the diencephalon?

• Processing, integrating, and relaying information to different parts of the brain
• Homeostasis maintenance (regulation of movement and biological rhythms)

What is the cerebellum separated into?

Right and left hemispheres

What is the function of the cerebellum?

• Planning, coordination, and monitoring of movement
• Motor learning for correction of motor error

What is the oldest part of the brain which connects the brain and spinal cord?

Brainstem

What are the functions of the brainstem?

• Maintenance of involuntary homeostatic functions (heart rate and breathing)
• Certain reflexes
• Movement monitoring
• Integration and relaying of information (sensation)
• Alertness maintenance

Where is the gray and white matter of the brain located?

Opposite of the spinal cord

Where is gray matter located in the brain?

The outer layer of the cerebrum and scattered in deeper regions

• Remainder is white matter

What are the bundles of white matter in the cerebrum called?

Tracts

Where do tracts receive and send information to?

Nuclei of the cerebral gray matter

What are the primary brain regions?

Developmental regions including the forebrain, midbrain, and hindbrain

What does the forebrain become?

Cerebrum and diencephalon

What does the midbrain become?

Part of the brainstem

What does the hindbrain become?

Cerebellum, pons, and medulla oblongata (brainstem)

What are the protective structures of the brain?

• Cranial meninges
• Cerebral spinal fluid (CSF)
• Blood-brain barrier

What are the layers of the cranial meninges?

1. Dura Mater (superficial)
2. Arachnoid Mater (middle)
3. Pia Mater (deep)

What is the dura mater layer of the cranial meninges?

• Outermost and thickest layer
• Blood vessels are in the epidural space
• Subdural space contains serous fluid and veins

What forms the dural sinuses?

Dura that drain CSF and deoxygenated blood

What is the arachnoid mater layer of the cranial meninges?

• Contains CSF and blood vessels.
• Granulations return CSF to the bloodstream

What is the pia mater layer of the cranial meninges?

• Covers the surface of the brain
• Permeable to substances in the extracellular fluid and CSF

What are ventricles?

Cavities in the brain which contain CSF

What connects the 3rd ventricle with the lateral ventricles?

Interventricular foramen

What drains the 3rd ventricle into the 4th ventricle?

Cerebral aqueduct

Which ventricle is continuous with the central canal of the spinal cord?

4th ventricle

What is cerebral spinal fluid (CSF)?

Clear colorless liquid similar to plasma

What are the functions of cerebral spinal fluid (CSF)?

• Brain protection by cushioning
• Temperature maintenance
• Waste removal
• Increasing buoyancy of the brain

How is cerebral spinal fluid (CSF) formed?

By the choroid plexus within each ventricle

Where are the choroid plexuses located?

Where fenestrated capillaries contact ependymal cells

What results from the increased intracranial pressure caused by the presence of excess cerebral spinal fluid (CSF)?

Hydrocephalus

What is the blood-brain barrier?

CSF and brain extracellular fluid separate from the blood

What does the blood-brain barrier consist of?

• Endothelium of capillaries
• Basal laminae
• Astrocytes

How does cerebral spinal fluid (CSF) circulate and how much of it?

150ml through the brain and spinal cord

What does a typical capillary allow?

Water and small solutes to move from the blood to the ECF

What do the astrocytes and tight junctions of the brain limit?

The solutes that enter the brain's ECF

What are the 2 characteristics of endothelial cells?

• Tighter junctions
• Limited endocytosis and exocytosis

What is the cerebrum composed of?

Left and right cerebral hemispheres with lateral ventricles

What are the sulci of the cerebrum?

Shallow grooves on the surface of the brain

What are the gyri of the cerebrum?

Elevated ridges on the surface of the brain