Questions and Answers
What develops from ectoderm arranged in a tubular structure called the neural tube?
Brain and spinal cord
What is the tubular structure formed early in the embryonic stage from which the central nervous system develops?
Neural tube
Which of the following are the three regions of the brain?
What does the prosencephalon give rise to?
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What does the telencephalon develop into?
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What does the diencephalon form?
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What is the function of the rhombencephalon?
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How many major parts does the adult brain consist of?
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What do ganglia refer to?
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Define nucleus in the context of the central nervous system.
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The brain consists of four ventricles filled with cerebrospinal fluid.
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Where is the third ventricle located?
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Where is the fourth ventricle located?
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What is cerebrospinal fluid's role?
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How does blood flow to the brain?
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How does the blood return to the heart from the brain?
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The adult brain receives 20% of the body's oxygen and glucose despite only being 2% of body weight.
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Without a continuous supply of glucose to the brain, a person will become __________.
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What does the blood-brain barrier do?
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How is the blood-brain barrier formed?
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What happens if the brainstem is affected?
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What is a cerebrovascular accident (stroke)?
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Name a degenerative brain disease characterized by beta-amyloid peptide deposits.
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What does the term flaccid paralysis refer to?
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Which connective tissue surrounds each nerve fiber?
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What connects each spinal nerve to a segment of the spinal cord?
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How many pairs of spinal nerves are there?
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What type of nerves are spinal nerves?
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Study Notes
Central Nervous System Development
- Brain and spinal cord develop from ectoderm as the neural tube.
- The neural tube is crucial in the early embryonic stage for forming the central nervous system.
Brain Regions and Functions
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Three primary regions of the brain:
- Prosencephalon (forebrain): develops into telencephalon and diencephalon.
- Mesencephalon (midbrain): forms the cerebral aqueduct and midbrain.
- Rhombencephalon (hindbrain): becomes metencephalon and myelencephalon.
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Telencephalon: develops into cerebrum and lateral hemispheres.
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Diencephalon: forms the thalamus, hypothalamus, epithalamus, and third ventricle.
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Metencephalon: develops into pons, cerebellum, and upper part of the fourth ventricle.
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Myelencephalon: forms medulla oblongata and lower part of the fourth ventricle.
Brain Structure and Components
- Adult brain consists of:
- Brain stem
- Cerebellum
- Diencephalon
- Cerebrum
Ventricular System
- The brain contains four ventricles filled with cerebrospinal fluid (CSF).
- Lateral ventricles: located in each cerebral hemisphere.
- Third ventricle: found in the diencephalon.
- Fourth ventricle: situated between pons and cerebellum; connected to the spinal cord's central canal.
Functional Areas of the Brain
- Sensory areas: involved in sensory information perception.
- Motor areas: control muscular movements.
- Association areas: responsible for complex functions including memory and intelligence.
Important Brain Structures
- Basal ganglia: coordinates gross muscle movements and regulates muscle tone.
- Limbic system: associated with emotional behavior critical for survival.
- Thalamus: relays almost all sensory input to the cerebral cortex and involves nuclei for movement planning.
- Hypothalamus: integrates autonomic nervous system activities, regulates emotional patterns, body temperature, and hormonal regulation.
- Epithalamus: contains the pineal gland, which secretes melatonin.
Brainstem and Cerebellum
- Brainstem: consists of medulla oblongata, pons, and midbrain, acting as a pathway for nerve impulses.
- Cerebellum: coordinates intended movement with actual movement for smooth coordination and balance.
Meninges and Cerebrospinal Fluid
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Three layers of cranial meninges:
- Dura mater: outermost, protective layer.
- Arachnoid mater: web-like structure providing cushion.
- Pia mater: thin layer closely adhering to brain and spinal cord.
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Cerebrospinal fluid: protects brain and spinal cord, transports nutrients and chemicals.
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Choroid plexus: network of capillaries producing CSF within the ventricles.
Blood Supply and Blood-Brain Barrier
- Blood flow to the brain primarily through internal carotid arteries; returns via internal jugular veins.
- Adult brain consumes 20% of oxygen and glucose despite being only 2% of body weight.
- Blood-brain barrier protects brain cells from harmful substances by restricting passage from blood to brain tissue.
Spinal Cord Anatomy
- The spinal cord is surrounded by protective structures: bone (vertebrae) and meninges.
- Located in the vertebral cavity, it connects to 31 pairs of spinal nerves.
- Spinal roots consist of sensory (posterior) and motor (anterior) axons.
Internal Structure of the Spinal Cord
- Gray and white matter: gray matter is shaped like an "H", surrounded by white matter with anterior and posterior gray horns serving different sensory and motor functions.
- Dorsal root ganglion: contains sensory neuron cell bodies.
Neurological Injuries and Disorders
- Concussion: caused by head trauma, leads to a temporary loss of function.
- Contusion: more severe, involves bruising of the brain leading to damage.
- Stroke: occurs when blood circulation is impaired leading to brain tissue death.
- Alzheimer's disease: degenerative brain disease marked by amyloid deposits and memory loss.
- Parkinson's and Huntington's diseases: characterized by abnormal movements due to neurotransmitter imbalances.
Connective Tissue in Nerves
- Endoneurium: surrounds individual nerve fibers.
- Perineurium: encases fascicles of nerve fibers.
- Epineurium: outer layer covering entire nerves.
Spinal Nerves and Their Functions
- Spinal nerves serve as communication pathways between the spinal cord and the body, consisting of sensory (afferent) and motor (efferent) fibers.
- Divided into rami for distribution to various body parts.
- Plexuses: networks formed from anterior rami, excluding thoracic nerves.
Summary of Spinal Nerve Anatomy
- Each typical spinal nerve comprises a posterior root (sensory input) and anterior root (motor output).
- Posterior ramus serves the trunk; anterior ramus supplies limbs and front trunk. Meningeal branches innervate the spinal cord covering.
- Damage to spinal structures can lead to conditions such as flaccid paralysis or sensory loss (paresthesias).
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Description
Explore the key concepts of the central and peripheral nervous system through these flashcards covering chapters 12 and 13. Each card provides an essential term and its definition to reinforce your understanding of neurological development and brain structure.
