Podcast
Questions and Answers
What color does gray matter appear and why?
What color does gray matter appear and why?
How many pairs of spinal nerves are there in the thoracic region?
How many pairs of spinal nerves are there in the thoracic region?
What type of neurons are found in the lateral horn of the gray matter?
What type of neurons are found in the lateral horn of the gray matter?
What does the gray commissure connect?
What does the gray commissure connect?
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Which part of the spinal cord contains an abundance of myelinated axons?
Which part of the spinal cord contains an abundance of myelinated axons?
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Which type of nerves contain both sensory and motor fibers?
Which type of nerves contain both sensory and motor fibers?
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How many pairs of lumbar spinal nerves are there?
How many pairs of lumbar spinal nerves are there?
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Which system conveys information from receptors to the brain?
Which system conveys information from receptors to the brain?
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What do the bundles of axons in the white matter carry?
What do the bundles of axons in the white matter carry?
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What is the central canal in the spinal cord filled with?
What is the central canal in the spinal cord filled with?
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Study Notes
The Spinal Cord
- The spinal cord is divided into 31 pairs of nerves, which are segmented into cervical, thoracic, lumbar, and sacral regions.
- The cord widens at two points: the cervical enlargement and the lumbar enlargement, where it gives rise to nerves of the upper and lower limbs.
- The lumbar enlargement and medullary cone give off a bundle of nerve roots called the cauda equina, which innervates the pelvic organs and lower limbs.
Cross-Sectional Anatomy of the Spinal Cord
- The spinal cord consists of two kinds of nervous tissue: gray matter and white matter.
- Gray matter has a dull color and contains neurons, while white matter contains an abundance of myelinated axons and appears bright and pearly white.
- In cross-section, the gray matter looks H-shaped, with two posterior (dorsal) horns and two wider anterior (ventral) horns.
The Brain
- The brain is part of the central nervous system and lies inside the cranial cavity.
- It consists of the cerebrum, cerebellum, midbrain, pons, and medulla oblongata.
- The brainstem is composed of the midbrain, pons, and medulla oblongata.
Major Parts of the Brain
- Forebrain: includes the cerebrum and diencephalon
- Midbrain: part of the brainstem
- Hindbrain: includes the medulla oblongata and cerebellum
Cerebrum
- The largest brain structure, divided into left and right hemispheres by the longitudinal cerebral fissure.
- Each hemisphere has an outer layer called the cerebral cortex, made of gray matter (nerve cell bodies).
- The layers below the cerebral cortex are white matter (nerve fibers).
- The cerebral cortex is divided into four lobes: frontal, parietal, temporal, and occipital.
Nervous System
- The nervous system is a major communicating and control system within the body.
- It works with the endocrine system to control many body functions and maintain homeostasis.
- The nervous system can be divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
- The CNS consists of the brain and spinal cord, while the PNS consists of peripheral nerves and ganglia.
Peripheral Nervous System
- The PNS can be divided into the afferent (sensory) and efferent (motor) divisions.
- The autonomic nervous system consists of the sympathetic and parasympathetic nervous systems.
- Neurons (nerve cells) cannot regenerate if damaged.
Brain and Spinal Cord
- The brain is continuous with the spinal cord through the foramen magnum.
- The spinal cord is divided into 31 pairs of nerves, which are attached to the spinal cord within the human body.
Spinal Nerves
- There are 31 pairs of spinal nerves, named and numbered according to the region and level of the vertebral column from which they emerge.
- The pairs are divided into:
- 8 cervical nerves
- 12 thoracic nerves
- 5 lumbar nerves
- 5 sacral nerves
- 1 coccygeal nerve
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Description
Explore the structure and function of the spinal cord, including its segmentation into cervical, thoracic, lumbar, and sacral regions.
