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Questions and Answers
What is the estimated number of neurons in the adult brain?
Which of the following components contributes to the protective layers of the brain?
What is the average weight of an adult human brain?
What percentage of the body's total blood flow does the brain receive per minute?
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Which type of matter primarily consists of neuronal cell bodies?
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Which type of tracts convey sensory information within the spinal cord?
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What type of receptors do proprioceptors provide information from?
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What is the main function of descending tracts in the spinal cord?
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What condition results from spinal cord damage affecting the legs and lower body?
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Which of the following components is NOT part of a reflex arc?
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Which type of reflex arc involves skeletal muscles as effectors?
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What is the characteristic of an autonomic reflex arc?
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What impact does spinal cord damage have on body function?
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What is primarily measured by an EEG?
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Which part of the brain is responsible for higher mental functions?
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Which EEG wave pattern is associated with relaxation and is typically seen with eyes closed?
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What type of brain matter consists of myelinated axons?
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What is indicated by the presence of Delta waves in an awake adult?
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What structure serves as the outer layer of gray matter in the brain?
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Which brain wave is associated with mental activity and visual stimulation?
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What does the tentorium cerebelli separate?
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What is the primary function of the sympathetic division of the autonomic nervous system?
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Which neurotransmitter is predominantly used by the sympathetic division in response to stress?
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How does the parasympathetic division of the autonomic nervous system primarily affect heart rate?
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What role do interneurons play in the autonomic nervous system?
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What is the contrasting effect of the parasympathetic division compared to the sympathetic division?
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Study Notes
Spinal Cord Anatomy
- The spinal cord is made up of gray matter, which is in the center, and white matter which surrounds it.
- The spinal cord extends from the foramen magnum to the first lumbar vertebra (L1).
- The white matter is made of ascending and descending fiber tracts.
- Gray matter is shaped like an "H" and has two dorsal (posterior) horns and two ventral (anterior) horns.
Ascending Tracts
- Ascending nerve tracts relay sensory information from the body to the brain.
- This information comes from:
- cutaneous receptors in the skin
- proprioceptors in muscles and joints
- visceral receptors in internal organs.
Descending Tracts
- Descending nerve tracts carry motor impulses from the brain to the body.
- These impulses stimulate muscle contractions.
Spinal Nerve Damage
- Nerves extend from the spinal cord down the spine.
- If the cord is damaged, function below the point of damage is impacted.
- Paraplegia results in paralysis of the legs and lower body.
- Quadriplegia results in paralysis of the arms and legs.
Reflex Arc
- A reflex arc is an unconscious motor response to a sensory stimulus.
- There are two main types of reflex arcs:
- Somatic reflex arcs - The effector is skeletal muscle.
- Autonomic reflex arcs - The effector is smooth muscles, cardiac muscle, glands.
- Each reflex arc includes:
- An interneuron in the central nervous system (CNS)
- A sensory neuron
- An effector (muscle or gland that responds)
- A somatic motor neuron
- A sensory receptor.
Central Nervous System (CNS)
- The CNS is made up of the brain and the spinal cord.
- The brain is responsible for higher-level functions such as thought, memory, and language.
- The spinal cord relays information between the brain and the body.
Brain Composition
- The adult brain has 100 billion neurons and weighs about 1.5 kg.
- The brain receives 15% of the body's total blood flow per minute.
- The brain is made up of gray matter (cell bodies and dendrites) and white matter (myelinated axons).
Brain Regions
- The cerebrum is responsible for higher mental functions.
- The cerebral cortex is the outer layer of the cerebrum, made up of gray matter with white matter underneath it.
- The cerebral cortex's activity is measured with an electroencephalogram (EEG).
EEG Wave Patterns
- EEGs measure brain function and health.
- EEG wave patterns reflect electrical potentials generated in brain cells.
- Higher frequency waves indicate higher levels of activity.
Somatic Reflex Arc
- Somatic reflex arcs involve a stimulus, a sensory neuron, an interneuron, a motor neuron and a muscle.
- An example of a somatic reflex is the knee-jerk reflex.
Autonomic Nervous Systems
- The ANS is part of the peripheral nervous system and controls involuntary functions such as heart rate, digestion, and breathing.
- It is made up of two divisions:
- The sympathetic nervous system
- The parasympathetic nervous system.
- The ANS uses two neurons: a preganglionic neuron and a postganglionic neuron.
Sympathetic Nervous System
- The sympathetic nervous system prepares the body for "fight or flight" responses.
- It releases norepinephrine (NE, adrenaline) to effectors.
- It increases heart rate, respiratory rate, and blood glucose.
- It also diverts blood flow from internal organs and skin to skeletal muscles.
Parasympathetic Nervous System
- The parasympathetic nervous system promotes "rest and digest" functions.
- It releases acetylcholine (ACh) to effectors.
- It slows heart rate, slows respiratory rate, and lowers blood glucose.
- It diverts blood flow from skeletal muscles to internal organs and skin, and increases digestive activity.
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Description
Test your knowledge on spinal cord anatomy, including its structure, ascending and descending tracts, and the implications of spinal nerve damage. This quiz covers key concepts essential for understanding the spinal cord's functions and its role in the nervous system.
