Physiology Lab 3 ✅

What are rapid involuntary stimuli responses called?

Reflexes

What are the simple nerve pathways that mediate reflexes?

Reflex arcs

What are the five essential components of a reflex arc?

Receptor, sensory neuron, integration center, motor neuron, effector

What is at the end of a sensory neuron reacting to stimuli?

Receptor

What conducts nerve impulses along an afferent pathway to the CNS?

Sensory neuron

What consists of one or more synapses in the CNS?

Integration center

What conducts nerve impulses along an efferent pathway from the integration center to an effector?

Motor neuron

What responds to the efferent impulses by contracting or secreting?

Effector

What type of reflex involves the activity of interneurons in the integration center?

Polysynaptic reflexes

What do polysynaptic reflexes involve?

More than 2 neurons

What increases response time in reflexes?

Increased synapses

What two neurons do monosynaptic neurons contain?

Motor and sensory neurons

What is a classic example of a monosynaptic neuron?

Knee-jerk reflex

How does the knee-jerk reflex work?

Tapping the tendon below the knee muscle stretches the thigh muscle, detected by a sensory neuron that sends the signal to a motor neuron.

Is there any brain input involved in the knee-jerk reaction?

No

What type of reflexes are initiated by an external stimulus to stimulate a skeletal muscle?

Somatic reflexes

What type of reflexes are initiated by either external or internal stimuli stimulating smooth muscle?

Autonomic or visceral reflexes

What are the further divisions of somatic reflexes?

Stretch, deep tendon, flexor withdrawal, crossed extension, primitive (neonatal) reflexes

What portion of the somatic reflex arc is damaged in someone with congenital insensitivity?

Integration center and sensory nerves

What portion of the somatic reflex arc is damaged in someone with congenital indifference?

Integration center and effectors

What kind of reflex arc is involved in the initiation of peristalsis in the stomach?

visceral

What is an important tool for assessing the condition of the nervous system?

Reflex testing

What do reflex tests help determine?

Location of spinal cord injury

What is an example of reflex testing to diagnose closed head injury?

Increased pressure on the oculomotor nerve (III) creates variation in eye reflex responses.

What does a 0 reflex grade indicate?

Absent reflex

What does a 1+ reflex grade indicate?

Sluggish or depressed reflex

What does a 2+ reflex grade indicate?

Normal reflex

What does a 3+ reflex grade indicate?

More brisk than usual reflex

What does a 4+ reflex grade indicate?

Clonus present (hyperactive reflex)

How does the patellar reflex work?

The muscle spindle in the quadriceps causes reflex contraction of the quadriceps muscles while the hamstrings relax.

What do stretch reflexes act to maintain?

Balance, posture, locomotion

In whom are stretch reflexes absent or hypoactive?

Those with peripheral nerve damage or ventral horn disease

In whom are stretch reflexes hyperactive?

Those with deep sedation or coma

What may asymmetrical stretch reflexes indicate?

Pathology

What reflex is elicited by the cutaneous skin receptor?

Nociception

What is the typical plantar reflex response?

Toes flex and move closer

What is an abnormal plantar reflex response?

Babinski sign

Why do infants exhibit the babinski response?

Underdeveloped myelination

What is the pupillary reflex?

Pupils change size to control light

What is the ipsilateral response in the pupillary reflex?

Pupil of the light receiving eye constricts

What is the consensual response in the pupillary reflex?

Pupil opposite to the receiving eye constricts

What is the accommodation reflex accomplished by?

Contraction of ciliary muscle and parasympathetic activity for near vision

What is the swallowing reflex?

Movement of food and saliva into the posterior oral cavity

What is a reaction?

Voluntary response

What is a reflex?

Involuntary response

What is stroke volume?

Amount of blood pumped with each beat

What are baroreceptors?

Sensors in the aortic arch and carotid arteries that respond to stretching

What sends signals to the medulla in response to stretching?

An increase or decrease in stretch

What do stretch signals sent to the medulla act on?

The heart through the vagus nerve

What does sudden increased pressure in the heart or carotid arteries result in?

Decreased heart rate