Human Physiology Chapter 10

What is perception?

The conscious interpretation of sensory information using sensory systems, memory, and neural processes.

What is sensory transduction?

Conversion of a stimulus into an action potential.

What happens after action potentials reach the brain?

They are converted into sensations.

What are sensory receptors?

Neurons that respond to stimuli by generating action potentials.

Difference between somatic and visceral receptors?

• Somatic → external (skin, muscles)

• Visceral → internal (organs)

What do chemoreceptors detect?

O₂, CO₂, and pH levels in blood.

What do baroreceptors detect?

Blood pressure.

What do mechanoreceptors (visceral) detect?

Stretch/distension in organs.

What does the somatosensory system detect?

Touch, pressure, temperature, pain, and body position.

What do proprioceptors do?

Detect body position.

What do mechanoreceptors detect?

Pressure, force, vibration.

What do thermoreceptors detect?

Temperature.

What do nociceptors detect?

Pain.

Function of dorsal column pathway?

Transmits touch and proprioception.

Function of spinothalamic tract?

Transmits pain and temperature.

Why is pain important?

It warns of potential tissue damage.

What are autonomic responses to pain?

↑ heart rate, ↑ blood pressure, sweating, pupil dilation.

What emotional responses can pain cause?

Fear and anxiety.

What is a reflexive pain response?

Withdrawal from stimulus.

What does the cornea do?

Allows light to enter the eye.

What is the sclera?

White outer layer of the eye.

Function of the lens?

Focuses light on the retina.

What does the iris do?

Controls pupil size and light entry.

What is the retina?

Layer with photoreceptors that detect light.

Difference between rods and cones?

• Rods → black & white

• Cones → color

What is the optic disc?

Blind spot (no rods or cones).

Path of visual signals to the brain?

Retina → optic nerve → optic chiasm → thalamus → visual cortex.

What is accommodation?

Adjustment of lens shape for focusing.

Lens shape for far objects?

Flat.

Lens shape for near objects?

Rounded.

What is myopia?

Near-sightedness.

What is hyperopia?

Far-sightedness.

What is astigmatism?

Irregular curvature causing blurry vision.

What is presbyopia?

Age-related lens stiffening.

What are cataracts?

Cloudy lens.

What is glaucoma?

Increased eye pressure.

What are the three parts of the ear?

External, middle, inner ear.

Function of external ear?

Collects sound.

Function of middle ear?

Amplifies sound via ossicles.

Name the ossicles.

Malleus, incus, stapes.

Function of cochlea?

Contains receptors for hearing.

What is the Organ of Corti?

Sensory organ for sound.

What causes action potentials in hearing?

Movement of stereocilia opens ion channels.

Which nerve carries hearing signals?

Vestibulocochlear nerve (CN VIII).

What structures control balance?

Semicircular canals, utricle, saccule.

What do semicircular canals detect?

Head movement/rotation.

Why is taste a chemical sense?

It detects chemicals in food.

Where are taste buds located?

Tongue, roof of mouth, pharynx.

Four primary tastes?

Salty, sour, sweet, bitter.

Which nerves carry taste signals?

Facial (VII), Glossopharyngeal (IX), Vagus (X).

What detects smell?

Olfactory receptor cells.

Which nerve carries smell signals?

Olfactory nerve (CN I).

Where is smell processed?

Olfactory bulb (frontal lobe).

What do taste and smell have in common?

Both are chemical senses and linked to memory and adaptation.