BIOS 252 Week 8 Final Exam Cover Page
,BIOS 252 Week 8 Final Exam – Essay Questions and Answers
1. Define spinal reflex and use an example from the body to illustrate a spinal reflex.
A spinal reflex is an automatic, rapid, involuntary response to a stimulus that is mediated primarily through the spinal cord without
requiring conscious involvement of the brain. Reflexes help protect the body from injury and maintain homeostasis.
A reflex pathway is called a reflex arc and usually includes:
1. Sensory receptor
2. Sensory (afferent) neuron
3. Integration center in the spinal cord
4. Motor (efferent) neuron
5. Effector organ (muscle or gland)
Example: Patellar (Knee-Jerk) Reflex
The patellar reflex occurs when the patellar tendon below the kneecap is tapped.
Process:
1. Tapping stretches the quadriceps muscle.
2. Muscle spindles detect the stretch.
3. Sensory neurons send impulses to the spinal cord.
4. In the spinal cord, the sensory neuron directly synapses with a motor neuron.
5. The motor neuron stimulates the quadriceps muscle to contract.
6. The lower leg kicks forward.
This is a monosynaptic reflex because only one synapse exists between sensory and motor neurons. The reflex helps maintain posture
and muscle tone.
,2. Describe sleep and its major stages and then contrast sleep to coma – how are they
similar and how do they differ.
Sleep is a natural, reversible state of altered consciousness characterized by decreased awareness and reduced responsiveness to
external stimuli. Sleep is essential for memory consolidation, tissue repair, metabolic regulation, and nervous system recovery.
Major Stages of Sleep
Sleep is divided into two major categories:
A. Non-Rapid Eye Movement (NREM) Sleep
Stage N1
Lightest stage of sleep
Transition from wakefulness to sleep
Slow eye movements
Reduced muscle activity
Stage N2
Deeper relaxation
Heart rate and temperature decrease
Sleep spindles and K-complexes appear on EEG
Stage N3 (Deep Sleep)
Slow-wave sleep
Difficult to awaken
Tissue repair and growth hormone release occur
B. Rapid Eye Movement (REM) Sleep
Most dreaming occurs
Brain activity resembles wakefulness
Skeletal muscles become temporarily paralyzed
, Important for learning and memory
Sleep cycles repeat every 90–110 minutes throughout the night.
Sleep vs. Coma
Similarities
Reduced awareness
Decreased responsiveness
Altered brain activity
Eyes usually closed
Differences
Sleep Coma
Natural and reversible Pathological condition
Cycles through stages No normal sleep cycles
Person can be awakened Cannot be awakened
Brain maintains organized activity Severe impairment of brain function
Restorative Usually indicates serious injury or disease
Coma commonly results from traumatic brain injury, stroke, metabolic disorders, or drug overdose.
3. Explain language usage and comprehension including a description of the two major
language areas of the brain.
Language involves both production and comprehension of spoken and written communication. Two major cortical regions are essential:
,BIOS 252 Week 8 Final Exam – Essay Questions and Answers
1. Define spinal reflex and use an example from the body to illustrate a spinal reflex.
A spinal reflex is an automatic, rapid, involuntary response to a stimulus that is mediated primarily through the spinal cord without
requiring conscious involvement of the brain. Reflexes help protect the body from injury and maintain homeostasis.
A reflex pathway is called a reflex arc and usually includes:
1. Sensory receptor
2. Sensory (afferent) neuron
3. Integration center in the spinal cord
4. Motor (efferent) neuron
5. Effector organ (muscle or gland)
Example: Patellar (Knee-Jerk) Reflex
The patellar reflex occurs when the patellar tendon below the kneecap is tapped.
Process:
1. Tapping stretches the quadriceps muscle.
2. Muscle spindles detect the stretch.
3. Sensory neurons send impulses to the spinal cord.
4. In the spinal cord, the sensory neuron directly synapses with a motor neuron.
5. The motor neuron stimulates the quadriceps muscle to contract.
6. The lower leg kicks forward.
This is a monosynaptic reflex because only one synapse exists between sensory and motor neurons. The reflex helps maintain posture
and muscle tone.
,2. Describe sleep and its major stages and then contrast sleep to coma – how are they
similar and how do they differ.
Sleep is a natural, reversible state of altered consciousness characterized by decreased awareness and reduced responsiveness to
external stimuli. Sleep is essential for memory consolidation, tissue repair, metabolic regulation, and nervous system recovery.
Major Stages of Sleep
Sleep is divided into two major categories:
A. Non-Rapid Eye Movement (NREM) Sleep
Stage N1
Lightest stage of sleep
Transition from wakefulness to sleep
Slow eye movements
Reduced muscle activity
Stage N2
Deeper relaxation
Heart rate and temperature decrease
Sleep spindles and K-complexes appear on EEG
Stage N3 (Deep Sleep)
Slow-wave sleep
Difficult to awaken
Tissue repair and growth hormone release occur
B. Rapid Eye Movement (REM) Sleep
Most dreaming occurs
Brain activity resembles wakefulness
Skeletal muscles become temporarily paralyzed
, Important for learning and memory
Sleep cycles repeat every 90–110 minutes throughout the night.
Sleep vs. Coma
Similarities
Reduced awareness
Decreased responsiveness
Altered brain activity
Eyes usually closed
Differences
Sleep Coma
Natural and reversible Pathological condition
Cycles through stages No normal sleep cycles
Person can be awakened Cannot be awakened
Brain maintains organized activity Severe impairment of brain function
Restorative Usually indicates serious injury or disease
Coma commonly results from traumatic brain injury, stroke, metabolic disorders, or drug overdose.
3. Explain language usage and comprehension including a description of the two major
language areas of the brain.
Language involves both production and comprehension of spoken and written communication. Two major cortical regions are essential:
