BIO 253 HONDROS EXAM FULLY SOLVED & UPDATED 2026
QUESTIONS AND ANSWERS
Job of Auditory (Eustachian) tube - ANSWER-maintains equal pressure on both sides of
tympanic membrane
connects middle ear to throat
Are cranial/spinal nerves PNS or CNS? - ANSWER-PNS
Tunic layers of Eye - ANSWER-Fibrous outer layer-sclera and cornea
Vascula middle layer-pigmented, cont. blood vessels
Nervous inner layer-retina, rods and cones
What are the ear stones? - ANSWER-Otoliths-help with balance and equilibrium
Receptors activated by specific action - ANSWER-Thermoreceptors
Nociceptors
Mechanoreceptors
Cranial nerves that control eye movement - ANSWER-Oculomotor
Trochlear
Abducens
Fovea Centralis - ANSWER-Part of Retina that contains the highest amount of photoreceptors
Optic Disc - ANSWER-Optic nerve exits through here
Pt of retina the has NO photoreceptors
where blood vessels enter eye
Sound transmission in ear - ANSWER-Pinna (auricle)--external auditory canal--tympanic
membrane (vibrates back and forth; pushes on the ossicles)--malleolus, incus, stapes--fluid in
the inner ear becomes wavy and stimulates mechanoreceptors (hair cells) in the cochlea
Which receptors never experience adaptation? - ANSWER-Nociceptors--Pain
Receptors controlled by being stretched or pushed on - ANSWER-Mechanoreceptors
ie-Bladder distention
, The receptor of the nose - ANSWER-chemoreceptors
Which structure contains tracts that carry nerve impulses to/from brain? - ANSWER-White
matter
Endocrine glands - ANSWER-ductless
release hormones
hormones travel through blood to targets
lamellated corpuscles - ANSWER-common in deeper subcut. tissues, tendons, ligaments
detect heavy pressure
tactile corpuscles - ANSWER-abundant in hairless portions of skin
detect light touch
microglia - ANSWER-perform phagocytosis, eat germs, clean up cellular debris when cells die
astrocytes - ANSWER-deliver nutrients
help form synapses
regulate fluid in interstial
ependymal cells - ANSWER-line ventricles
move CSF
circulate CSF in ventricle of brain and central canal of spinal cord
oligodendrocytes - ANSWER-make up myelin sheath in CNS
schwann cells - ANSWER-make up myelin sheath in PNS
depolarization - ANSWER-Na+ channels open and Na+ moves inside cell
inside the cell becomes more positive
repolarization - ANSWER-K+ moves out of cell
goes back to normal state
inside cell becomes more negative
ventral roots of spinal cord - ANSWER-motor neurons
multipolar
QUESTIONS AND ANSWERS
Job of Auditory (Eustachian) tube - ANSWER-maintains equal pressure on both sides of
tympanic membrane
connects middle ear to throat
Are cranial/spinal nerves PNS or CNS? - ANSWER-PNS
Tunic layers of Eye - ANSWER-Fibrous outer layer-sclera and cornea
Vascula middle layer-pigmented, cont. blood vessels
Nervous inner layer-retina, rods and cones
What are the ear stones? - ANSWER-Otoliths-help with balance and equilibrium
Receptors activated by specific action - ANSWER-Thermoreceptors
Nociceptors
Mechanoreceptors
Cranial nerves that control eye movement - ANSWER-Oculomotor
Trochlear
Abducens
Fovea Centralis - ANSWER-Part of Retina that contains the highest amount of photoreceptors
Optic Disc - ANSWER-Optic nerve exits through here
Pt of retina the has NO photoreceptors
where blood vessels enter eye
Sound transmission in ear - ANSWER-Pinna (auricle)--external auditory canal--tympanic
membrane (vibrates back and forth; pushes on the ossicles)--malleolus, incus, stapes--fluid in
the inner ear becomes wavy and stimulates mechanoreceptors (hair cells) in the cochlea
Which receptors never experience adaptation? - ANSWER-Nociceptors--Pain
Receptors controlled by being stretched or pushed on - ANSWER-Mechanoreceptors
ie-Bladder distention
, The receptor of the nose - ANSWER-chemoreceptors
Which structure contains tracts that carry nerve impulses to/from brain? - ANSWER-White
matter
Endocrine glands - ANSWER-ductless
release hormones
hormones travel through blood to targets
lamellated corpuscles - ANSWER-common in deeper subcut. tissues, tendons, ligaments
detect heavy pressure
tactile corpuscles - ANSWER-abundant in hairless portions of skin
detect light touch
microglia - ANSWER-perform phagocytosis, eat germs, clean up cellular debris when cells die
astrocytes - ANSWER-deliver nutrients
help form synapses
regulate fluid in interstial
ependymal cells - ANSWER-line ventricles
move CSF
circulate CSF in ventricle of brain and central canal of spinal cord
oligodendrocytes - ANSWER-make up myelin sheath in CNS
schwann cells - ANSWER-make up myelin sheath in PNS
depolarization - ANSWER-Na+ channels open and Na+ moves inside cell
inside the cell becomes more positive
repolarization - ANSWER-K+ moves out of cell
goes back to normal state
inside cell becomes more negative
ventral roots of spinal cord - ANSWER-motor neurons
multipolar
