The Spinal Cord and The Spinal Nerves

These flashcards cover key concepts and facts about the spinal cord and spinal nerves as discussed in Dr. Khalil Saadipour's physiology lecture.

What is the primary function of the spinal cord?

To process reflexes, integrate EPSP and IPSP, and conduct sensory and motor impulses.

What protects the spinal cord?

Bone (vertebrae), connective tissue (meninges), and cerebrospinal fluid.

What are the three layers of the meninges?

Dura mater, Arachnoid mater, Pia mater.

Where does the spinal cord start and end?

It starts at the foramen magnum and ends around the 2nd lumbar vertebra (L2).

What is the central canal in the spinal cord?

A fluid-filled space in the spinal cord.

What are the two main types of matter in the spinal cord?

Gray matter and white matter.

What does gray matter contain?

Neuron cell bodies and unmyelinated axons.

What does white matter contain?

Myelinated axons.

How many pairs of spinal nerves do humans have?

31 pairs.

What are the cervical nerves?

Cervical nerves are eight pairs (C1-C8) that supply the neck and upper limbs.

What is the role of the phrenic nerve?

Controls the diaphragm for breathing.

Which spinal nerves comprise the brachial plexus?

C5-T1 spinal nerves.

What is the main function of the lumbar plexus?

Supplies muscles of the anterior and medial thigh, and abdominal muscles.

What areas of the body does the sacral plexus supply?

Muscles of the leg, foot, gluteal muscles, and perineum.

What are dermatomes?

Areas of skin supplied by a spinal nerve.

What does a reflex arc consist of?

A sensory receptor, sensory neuron, integrating center, motor neuron, and effector.

What type of response is a reflex?

A fast, predictable, automatic response to changes in the environment.

What is the role of interneurons in reflexes?

They serve as the integrating center relaying impulses from sensory to motor neurons.

What is the stretch reflex?

A reflex that controls muscle length by causing muscle contraction.

What is the tendon reflex?

A reflex that controls muscle tension by causing muscle relaxation.

How does the brain perceive pain during a heart attack?

Pain is felt in the chest, shoulder, and neck due to nerve pathways converging.

What happens if a reflex is absent or abnormal?

It may indicate damage along the respective nerve pathway.

What connects sensory and motor pathways in the spinal cord?

Interneurons.

What is the anterior median fissure?

A groove that divides the spinal cord into right and left halves.

Where do the spinal nerves emerge from?

The spinal cord.

What are the segments of the spinal cord?

Cervical, thoracic, lumbar, sacral, and coccygeal.

What is the significance of the lumbar enlargement?

It accommodates nerves that supply the lower limbs.

What is the role of cerebrospinal fluid?

To cushion and protect the spinal cord.

What is the function of the sensory neuron?

To carry impulses from receptors to the integrating center.

What do skeletal muscles receive impulses from?

Somatic motor neurons.

Which spinal nerves form the cauda equina?

Lumbosacral spinal nerves.

What is the anterior root of the spinal nerve?

Contains axons of motor neurons.

What region does the thoracic plexus supply?

Upper limbs and parts of the torso.

What do reflexes help to maintain?

Homeostasis.

What detects muscle tension during the tendon reflex?

Golgi tendon organs.

What is the main role of sensory neurons?

To transmit sensory information to the central nervous system.

What is the basic function of the spinal cord regarding reflexes?

It serves as an integrating center.

What does the term 'subarachnoid space' refer to?

The space between the arachnoid mater and pia mater containing cerebrospinal fluid.

Content of the posterior gray horn includes which type of neurons?

Sensory interneurons.

What determines the specific area innervated by a spinal nerve?

Dermatome map.

How many total spinal nerves should one find in the human body?

There are 31 pairs totaling 62 spinal nerves.

What is a clinical use of reflex testing?

To diagnose potential nervous system issues.

What is the anterior gray horn responsible for?

Housing somatic motor neuron cell bodies.

Explain the role of the central canal.

It circulates cerebrospinal fluid and maintains homeostasis.

What identifies a spinal nerve's unique spinal cord segment?

Its specific pair number (C1-S5).

How do spinal nerves contribute to motor functions?

They send motor impulses to effectors, like muscles.