Midbrain (Mesencephalon) : Short section of the brain stem
Superior colliculi (visual reflexes)
Inferior colliculi (auditory reflexes)
Cerebral peduncles (coordinates reflexes)
Pituitary : has endocrine functions
Pons: Relays impulse form one region of the brain to another: Many cranial nerves originate here: Involved with regulating respiratory rate.
Thalamus: relay center for all sensory impulses to cerebral cortex, except for smell.
7. Label the parts of the eye below.
In the cow eye, there was a shiny layer at the back of the eye called the tapetum. What purpose does this structure serve? Do humans have one? What does this imply?
The Tapetum is responsible for night vision. Humans do not have one therefore we do not have very good night vision.
What are the photoreceptors in the eye? What is the role of each?
Rods – responsible for night vision (black and white) vision
Cones responsible for daytime (color) vision
Choroid: Supplies nutrients and oxygen to the eye
List the functions of the following eye structures:
External muscles : Move the eye around
Retina: A thin layer of cells that convert light into nerve signals
Cornea: Works with the lens to refract light and helps the eye to focus
Lens: A clear structure that refracts light and can change in curvature
Optic Nerve: Transmits signals from the eye to the brain
Iris: The pigmented ring of muscles that change the size of the pupil
Sclera: Gives the eye its shape and protects the inner parts
Ciliary Muscles: A tiny ring of muscles that change the shape of the lens
Compare and contrast the aqueous humor and vitreous humor found in the eye.
Aqueous humor found in the anterior cavity of the eye and is a watery substance.
Vitreous humor is found in the posterior cavity of the eye and is a jelly-like substance.
List the steps of vision in order.
Light rays pass through the pupil and hit the lens.
The lens must change shape to focus light on the retina
Light rays hit the photoreceptors in the retina
Nerve impulses are carried along the optic nerve to the optic chiasma and to the occipital lobe of the cerebrum.
What does a normal lens look like? Why does its appearance change? What do we call this condition?Biconvex structure It changes shape to focus light on the retina - (The farther away an object, the flatter the lens must become Adjustments in shape are controlled by the ciliary muscles in the ciliary body.
Cataracts causes the lens to become cloudy .
Write the function of the following ear structures:
Auricle: Directs sound waves to the external auditory canal (pinna)
External auditory canal: A 2.5cm fleshy tube that fits into the bony external acoustic meatus
Tympanic membrane: Conducts sound waves to the middle ear (eardrum)
Auditory ossicles: Three small bones (hammer, anvil, & stirrup) that amplify sound waves
Auditory (Eustachian) tube: Connects the middle ear cavity to the pharynx; Drains moisture from the middle ear cavity to equalize pressure on both sides of the eardrum
Semicircular Canals: Contain receptors that are sensitive to the rotation of the head
Vestibular window: Transfers sound waves from the auditory ossicles to the cochlea
Conchlea: Contains hair cells that vibrate and send nerve impulses to the cochlear nerve
List the steps for hearing in order.
Sound waves are funneled by the auricle into the external auditory meatus