A&P I Final Exam

What are the four primary functions of the spinal cord?

Conduction, neural integration, locomotion, and reflexes

What is meant by conduction in the spinal cord?

Transmission of sensory input to the brain and motor output to effectors

How does the spinal cord contribute to neural integration?

It processes incoming sensory information and generates appropriate motor responses

What role does the spinal cord play in locomotion?

It contains central pattern generators that coordinate repetitive movements like walking

What defines a reflex?

A rapid, automatic response to a stimulus

What is the function of the cervical enlargement?

Supplies nerves to the upper limbs

What is the function of the lumbosacral enlargement?

Supplies nerves to the lower limbs

Where does the spinal cord typically end in adults?

At the level of L1–L2 vertebrae

What is the conus medullaris?

The tapered, cone-shaped end of the spinal cord

What is the cauda equina?

A bundle of spinal nerve roots extending below the spinal cord

What is the function of the filum terminale?

Anchors the spinal cord to the coccyx

What is the lumbar cistern and why is it clinically important?

A CSF-filled space used for lumbar punctures

What are the three layers of the spinal meninges?

Dura mater, arachnoid mater, pia mater

What is located in the epidural space?

Fat and blood vessels

What fills the subarachnoid space?

Cerebrospinal fluid (CSF)

What structures are found in the CNS versus the PNS?

CNS: nuclei and tracts; PNS: ganglia and nerves

What structural components make up white matter?

Myelinated axons

What structural components make up gray matter?

Neuron cell bodies, dendrites, and synapses

What is the function of the central canal?

Circulates cerebrospinal fluid through the spinal cord

What type of neurons are located in the anterior horn?

Somatic motor neurons

What type of information is processed in the posterior horn?

Sensory information

What is the role of the lateral horn?

Contains autonomic motor neurons

What are the three funiculi of spinal white matter?

Posterior, lateral, and anterior funiculi

Where are sensory tracts primarily located in the spinal cord?

Posterior and lateral funiculi

Where are motor tracts primarily located in the spinal cord?

Anterior and lateral funiculi

What is the function of ascending tracts?

Transmit sensory information to the brain

What is the function of descending tracts?

Transmit motor commands from the brain

What does decussation mean in neural pathways?

Crossing from one side of the body to the other

What is the difference between contralateral and ipsilateral pathways?

Contralateral cross sides; ipsilateral remain on the same side

What type of sensory information is transmitted by the posterior column pathway?

Fine touch, vibration, and proprioception

Where do second-order neurons of the posterior column pathway cross?

In the medulla

Where is sensory information from this pathway ultimately processed?

Primary somatosensory cortex

What type of sensory information is transmitted by the spinothalamic pathway?

Pain, temperature, and crude touch

Where does the spinothalamic pathway decussate?

In the spinal cord

Where do upper motor neurons originate?

In the cerebral cortex

Where are lower motor neuron cell bodies located?

In the anterior horn of the spinal cord

What are the five components of a reflex arc?

Receptor, sensory neuron, integration center, motor neuron, effector

What is an example of a stretch reflex?

Patellar (knee-jerk) reflex

What is the purpose of the flexor (withdrawal) reflex?

To remove a body part from a painful stimulus

What is the function of the crossed extension reflex?

Maintains balance during withdrawal

Where is a lumbar puncture performed and why?

In the lumbar cistern to collect CSF safely

What are common symptoms of meningitis?

Fever, stiff neck, headache

What causes shingles and where does it originate?

Varicella-zoster virus in dorsal root ganglia

What is a dermatome?

An area of skin supplied by a single spinal nerve

Why are dermatomes clinically important?

They help identify nerve damage or compression

How many pairs of spinal nerves are there?

31 pairs

How many cervical spinal nerves exist?

8 pairs

How many thoracic spinal nerves exist?

12 pairs

How many lumbar spinal nerves exist?

5 pairs

How many sacral spinal nerves exist?

5 pairs

What structures are controlled by the autonomic nervous system?

Glands, smooth muscle, and cardiac muscle

Is the autonomic nervous system under voluntary or involuntary control?

Involuntary

How does the ANS pathway differ from the somatic motor pathway?

It uses a two-neuron chain

Where does the preganglionic neuron originate and what does it release?

In the CNS; releases acetylcholine

What is the role of the postganglionic neuron?

It transmits signals from ganglion to target tissue

What are the two main divisions of the ANS?

Sympathetic and parasympathetic

What is the function of the sympathetic division?

Prepares the body for stress (“fight or flight”)

What is the function of the parasympathetic division?

Promotes rest and digestion

Where does the sympathetic division originate?

Thoracolumbar region (T1–L2)

What is the general length pattern of sympathetic fibers?

Short preganglionic, long postganglionic

Where are sympathetic ganglia located?

Near the spinal cord

What neurotransmitter is most commonly released by sympathetic postganglionic neurons?

Norepinephrine

Where does the parasympathetic division originate?

Craniosacral regions

What is the fiber length pattern of parasympathetic neurons?

Long preganglionic, short postganglionic

What neurotransmitter is released by parasympathetic postganglionic neurons?

Acetylcholine

Which neurotransmitters bind to adrenergic receptors?

Norepinephrine and epinephrine

Which neurotransmitter binds to cholinergic receptors?

Acetylcholine

Where are nicotinic receptors found?

On postganglionic neurons in ganglia

Where are muscarinic receptors found?

On target organs

How does sympathetic stimulation affect the heart?

Increases heart rate and force

How does sympathetic stimulation affect the lungs?

Causes bronchodilation

How does sympathetic stimulation affect digestion?

Inhibits digestive activity

How does parasympathetic stimulation affect digestion?

Enhances digestive activity

What are white rami communicantes?

Preganglionic sympathetic fibers

What are gray rami communicantes?

Postganglionic sympathetic fibers

What are sympathetic chain (paravertebral) ganglia?

Ganglia running alongside the spinal cord

What are collateral ganglia?

Ganglia located near target organs

What is the function of the enteric nervous system?

Controls gastrointestinal activity

What makes the enteric system unique?

It can function independently of the CNS

What is the effect of alpha-1 receptor activation?

Vasoconstriction

What is the effect of beta-1 receptor activation?

Increases heart activity

What is the effect of beta-2 receptor activation?

Bronchodilation

How do beta blockers affect the body?

Reduce heart rate

How do alpha blockers affect blood vessels?

Cause relaxation (vasodilation)

What does dual innervation mean?

Organs receive input from both ANS divisions

What are the three major regions of the brain?

Cerebrum, cerebellum, brainstem

What does the term rostral refer to in the brain?

Toward the front (forehead)

What does the term caudal refer to?

Toward the spinal cord

What is the largest part of the brain?

Cerebrum

What is the function of the precentral gyrus?

Voluntary motor control

What is the function of the postcentral gyrus?

Somatic sensory processing

Why are gyri important?

They increase surface area for more neurons

What functions are associated with the frontal lobe?

Decision-making, motor control

What functions are associated with the parietal lobe?

Sensory processing

What functions are associated with the temporal lobe?

Hearing and memory

What functions are associated with the occipital lobe?

Vision

What structures make up the brainstem?

Midbrain, pons, medulla

What vital functions are controlled by the medulla oblongata?

Heart rate, breathing, blood pressure

What is the role of the pons?

Breathing regulation and signal relay

What is the role of the midbrain?

Reflexes related to vision and hearing