BIO 2301 Human Physiology - Exam 1 (CSCC - SU18)
Actual 2025/2026 181 Questions And 100% Verified
CORRECT Answers
Homeostasis
The body's ability to maintain internal stability, even in the face
of external change
Components of a homeostatic mechanism
- Control center: usually found in the hypothalamus of the
brain, contains the "set point" for the variable, receives info
from the receptors and sends instructions to effectors
- Receptors: detect or sense the variable and send that info to
the control center
- Effectors: receive instructions from the control center and
carry them out to get the variable back to normal
Examples of homeostatic mechanisms
- The maintenance of body temperature
- Blood glucose levels
- Blood sodium levels
- Blood pressure
,Negative feedback
- When a change in the variable occurs, the body responds by
causing a change in the opposite direction
- The main way that homeostatic mechanisms work
What do the ossicles help do?
Amplify sound
Organ of corti
- The receptor for hearing
- Found in the cochlear duct of the cochlea
Structure of the organ of corti
- Contains hair cells (stereocilia) that are embedded in the
tectorial membrane
- Sits on the basiliar membrane
Vibration of the cilia of the hair cells
- This will cause action potentials which will then travel up the
CN VIII to the brain where conscious perception (hearing)
actually occurs
,What determines pitch discrimination?
The basilar membrane
What determines amplitude discrimination?
The number of hair cells stimulated
Conduction deficit
- Occurs when the sound vibrations cannot be conducted to
the inner ear along the normal conduction pathway
- Can be caused by fused ossicles, a ruptured eardrum,
increased wax pressing against the eardrum, etc.
- Treatments include hearing aids to amplify the sound and
send the vibrations through the bones to the inner eart
Nerve deficit
- Occurs when there is damage to the neurons in the inner ear
- No treatment although cochlear implants help some people
How can you distinguish between conduction deficits and
nerve deficits?
, By having a person hum to vibrate their skull - if they can hear
it, then there is a conduction deficit and it will sound louder in
the deaf ear; if they cannot hear it, it is nerve deficit
Vestibular function
- Also known as equilibrium or balance
- Controlled by the cerebellum of the brain
- The cerebellum receives info from: the eyes, the vestibular
apparatus (utricle, saccule, and ampulla of the semicircular
canals), and the kinesthetic receptors (found in the joints - tell
info on proprioception, where the limbs are in space)
- Balance can be maintained as long as the cerebellum gets
info from 2 out of 3 of those sites
Utricle and sccule
- Found in the vestibule of the inner ear
- Detect linear acceleration of the head or head tilt (moving
head up and down or back and forth)
Ampulla of the semicircular canals
- Found in the inner ear
- Detect rotation of the eat (shaking head, tipping head to
shoulder)
Actual 2025/2026 181 Questions And 100% Verified
CORRECT Answers
Homeostasis
The body's ability to maintain internal stability, even in the face
of external change
Components of a homeostatic mechanism
- Control center: usually found in the hypothalamus of the
brain, contains the "set point" for the variable, receives info
from the receptors and sends instructions to effectors
- Receptors: detect or sense the variable and send that info to
the control center
- Effectors: receive instructions from the control center and
carry them out to get the variable back to normal
Examples of homeostatic mechanisms
- The maintenance of body temperature
- Blood glucose levels
- Blood sodium levels
- Blood pressure
,Negative feedback
- When a change in the variable occurs, the body responds by
causing a change in the opposite direction
- The main way that homeostatic mechanisms work
What do the ossicles help do?
Amplify sound
Organ of corti
- The receptor for hearing
- Found in the cochlear duct of the cochlea
Structure of the organ of corti
- Contains hair cells (stereocilia) that are embedded in the
tectorial membrane
- Sits on the basiliar membrane
Vibration of the cilia of the hair cells
- This will cause action potentials which will then travel up the
CN VIII to the brain where conscious perception (hearing)
actually occurs
,What determines pitch discrimination?
The basilar membrane
What determines amplitude discrimination?
The number of hair cells stimulated
Conduction deficit
- Occurs when the sound vibrations cannot be conducted to
the inner ear along the normal conduction pathway
- Can be caused by fused ossicles, a ruptured eardrum,
increased wax pressing against the eardrum, etc.
- Treatments include hearing aids to amplify the sound and
send the vibrations through the bones to the inner eart
Nerve deficit
- Occurs when there is damage to the neurons in the inner ear
- No treatment although cochlear implants help some people
How can you distinguish between conduction deficits and
nerve deficits?
, By having a person hum to vibrate their skull - if they can hear
it, then there is a conduction deficit and it will sound louder in
the deaf ear; if they cannot hear it, it is nerve deficit
Vestibular function
- Also known as equilibrium or balance
- Controlled by the cerebellum of the brain
- The cerebellum receives info from: the eyes, the vestibular
apparatus (utricle, saccule, and ampulla of the semicircular
canals), and the kinesthetic receptors (found in the joints - tell
info on proprioception, where the limbs are in space)
- Balance can be maintained as long as the cerebellum gets
info from 2 out of 3 of those sites
Utricle and sccule
- Found in the vestibule of the inner ear
- Detect linear acceleration of the head or head tilt (moving
head up and down or back and forth)
Ampulla of the semicircular canals
- Found in the inner ear
- Detect rotation of the eat (shaking head, tipping head to
shoulder)
