Anatomy and phys 2 chptr 13

Distinguish between sensation and perception

Sensation: the awareness of changes in the internal and external environment.

Perception: the consciousness interpretation of those stimuli

What are sensory receptors

Sensory receptors are specialized to respond to changes in environment ( stimuli )

What stimulus: Mechanoreceptors

Stimulus: mechanical force ( touch, pressure, stretch )

Location example: Ski, joints, muscles

What stimulus: Thermoreceptors

Stimulus: temperature changes

Location example: Skin

What stimulus: Photoreceptors

Stimulus: Light

Location example: Retina

What stimulus: Chemoreceptors

Stimulus: Chemicals in solution

Location example: tongue, nose, blood.

What stimulus: Nociceptors

Stimulus: damage ( stimuli, tissues )

Location example: everywhere except brain tissue

What are the three levels of neural integration in the somatosensory system

1. Receptor level

2. Circuit level

3. Perceptual level.

Receptor level: define transduction and what must happen for sensation to occur

For transduction; the energy of stimulus is converted to grade potential which must reach a threshold to initiate action potential. The action potential must reach the CNS for sensation to occur.

Adaptation: distinguish between phasic receptors ( fast adapting ) and tonic receptors (slow adapting/non adapting)

Phasic receptor: fast, strong, brief, fades. Example: keep brain from feeling overwhelmed

Tonic receptors: Slow, sustained response. Example: pain (noicioceptors ) and balance ( proprioters )

Perceptual level: where does the interpretation of sensory input occur

The cerebral cortex

Pain Perception: what is referred pain. Why does visceral pain often felt in specific somatic areas.

Refered pain is pain felt in one body region perceived as coming from another region. Viceral pain happens because of the way the pain fibers travel, things can get mixed up.

Define a nerve. What is the difference between sensory ( afferent ) and motor ( efferent ) devisions

A nerve is a cordlike organ consisting of a group of axons in the pns.

Sensory ( afferent ) is Towards CNS

Motor ( efferent ) is away CNS

Define a mixed nerve. Explain why the majority of nerves fall into this category, compared to pure sensory or motor nerves.

A mixed nerve is a nerve that contains both sensory and motor fibers. Other one idk

How many pairs of spinal nerves are there total?

31 nerves

8 cervical

12 thoracic

5 lumbar

5 sacral

1 tiny coccygeal

How do the nerves of c1-c7 exit ( above or below )

They exit the vertebral canal superior to the vertebrae

C7 has two exits, one above and one below.

C8 exits inferior to C7

What is the Dorsal ramus

Distributes sensory and motor Innervation to the back

What is ventral ramus

Distributes sensory and motor innervation to body wall and limbs

What is the meningeal branch

Re enters the vertebral canal to serve the meninges and vertebrae

What is a nerve plexus and why is it important

All ventral rammi ( except T1 and T12 ) form INTERLACING NERVE NETWORKS (nerve plexus )

It is important because it is. LOL

What is the cervical plexus, Key nerve?

( C1-C4 ) innervates anterior neck muscles, skin of neck, back of head, shoulder.

Key nerve: Phrenic nerve ( diaphragm )

What is the brachial plexus, Key nerve?

Innervates upper limb ( shoulder, arm forearm, hand )

Key nerves: axllary, radial, ulnar

What is the lumbar plexus. Key nerve?

Innervates anterior and medial thigh, abdominal wall.

Key nerve: femoral and obturator

What is the sacral plexus

Innervates pelvis, buttox, posterior thigh, lower limb, and foot.

Key nerves: sciatic ( tibia and common fibular )

What are the five components of a reflex arc

Receptor

Sensory neuron

Integration center

Motor neuron

Effector

What is a receptor in the reflex arc

Detects stimulus

What is the sensory neuron in the reflex arc

Transmits impulses from receptor to CNS integration center

What is the integration center in the reflex arc

Interneurons in CNS that issue a motor response

What is the motor neuron in the reflex arc

Conducts efferent impulses from integration center to effector

What is the effector in the reflex arc

Muscle fibers react by contracting or secreting

Somatic in reflex

Activate skeletal muscle

Example: knee jerk reflex

Autonomic in reflex

Viceral effectors such as smooth or cardiac muscle

Example: pupillary light reflex