BMS 302 Exam 2 part 1

glycogenesis

glucose to glycogen

glycogenolysis

glycogen to glucose

gluconeogenesis

amino acids and glycerol to glucose

lipogenesis

glucose to lipids

lipogenesis is a ______ process that occurs primarily ______.

synthetic; following a meal

glycogenolysis is a ______ process that occurs primarily ______.

degradative; during a fasting state

glycogenesis is a ______ process that occurs primarily ______.

synthetic; following a meal

lipolysis is a ______ process that occurs primarily ______.

degradative; during a fasting state

gluconeogenesis is a ______ process that occurs primarily ______.

synthetic; during a fasting state

what reduces blood glucose levels

glycogenesis and lipogenesis

what increases or returns blood glucose to the steady state level

glycogenolysis and gluconeogenesis

Which of the following cells require the presence of insulin before glucose can be transported across the cell membrane?

muscle cells, adipose tissue, and most other cells of the body

What cells in the pancreas are responsible for detecting changes (both increases and decreases) in blood glucose levels?

beta

insulin functions

1. activates glucose transporter molecules

2. decreases blood glucose levels

3. release is stimulated by increased blood glucose levels

4. is released from beta cells in the pancreas

what metabolic processes are stimulated by or require the presence of insulin

glycogenesis and lipogenesis

glucagon functions

1. increases blood glucose levels

2. release is stimulated by decrease blood glucose levels

3. is released from alpha cells in the pancreas

Which metabolic processes are stimulated by glucagon in the liver?

glycogenolysis and gluconeogenesis

T/F: Only glucagon is released during fasting and only insulin is released following a meal.

false

epinephrine functions

1. increases blood glucose levels

2. release is stimulated by stress

3. is released from the medullary cells of the adrenal gland

4. is a hormone

what metabolic process is stimulated by epinephrine

glycogenolysis

hyperglycemia

glucose remains in the blood because it cannot be transported into cells for use and storage

glucosuria

glucose levels in blood become so high that they exceed the kidney's ability to reabsorb glucose so glucose is found in the urine

polyuria

increased osmolality of urine due to glucose in urine causes large quantities of fluid to be excreted in an attempt to dilute urine

polydipsia

dehydration results in an increased thirst as the body attempts to rehydrate

acidosis

ketones released for energy result in a decreased blood pH

Type 1 diabetes is characterized by

decreased insulin production

type 2 diabetes is characterized by

decreased receptor number or function

Type 1 diabetes is diagnosed by fasting blood glucoses:

greater than or equal to 126 mg%

Type 2 diabetes is diagnosed by fasting blood glucoses

greater than or equal to 126 mg%

diabetic coma is characterized by

too little insulin, hyperglycemia

insulin shock is characterized by

too much insulin, hypoglycemia

treatment for diabetic coma

insulin injections

treatment for insulin shock

glucose or glucagon injections

A diagnosis of diabetes can be made if the fasting blood glucose is

>126 mg%

When reporting blood glucose levels units may be:

1. mg%

2. mg/dl

3. mg/ 100 mL

Which photoreceptor is responsible for night (low acuity, low light threshold) vision?

rods

Which photoreceptor is responsible for color (high acuity, high light threshold) vision?

cones

The relative concentrations of cones is greater in the _____ than the _____ of the retina.

fovea; periphery

The relative concentrations of rods is greater in the _____ than the _____ of the retina.

periphery; fovea

The fovea:

1. provides the area of greatest acuity

2. is where we direct our focus when trying to view an object

3. is the area where the four layers of accessory neurons and blood are pulled to the side

4. allows light to directly stimulate the cones

The site where the optic nerve and blood vessels leave the retina:

is the blind spot and has no photoreceptors

What two factors determine the refractive power of a lens?

1. The difference in the refractive indices of the two media (air:aqueous solution, air:glass, aqueous solution:glass, water:aqueous solution, etc.)

2. the angle at which light enters a lens

The interface which produces the most refraction of light in the normal eye is

air- cornea

List the four components of the refractive system of the eye in order from the air to the retina.

cornea→ aqueous humor → lens → vitreous humor

Which of the four components of the eye's refractive system is not fixed and can change its refractive power as needed?

lens

focal point

point at which light converges behind a lens

focal length

distance between the lens and the focal point

convex lens

lens that causes light rays to converge

concave lens

lens that causes light rays to diverge

concave grouping

diverging, negative diopter

convex grouping

converging, positive diopter

what are associated with emmetropia

1. focal point on the retina

2. focal length= 17 mm

3. refractive power of lens system= 59 diopters

what are the three reflexes associated with the near response?

accomodation, pupillary, and convergence

what does the accommodation reflex do to the refractive power of the eye lens?

increase

why is the accommodation reflex necessary to focus the image of a near object on the retina? Near light rays are ___ and require a ____ refractive power to focus on the retina

diverging; greater

In the accommodation reflex, the ciliary muscle _______, which ______ the tension on the suspensory ligaments, and _____ the refractive power of the lens.

contracts; decreases; increases

contraction of the ciliary muscle is the result of

increased PANS

relaxation of the ciliary muscle is the result of

decreased PANS

what type of muscle is the ciliary muscle

multi-unit smooth

Eye drops containing atropine, a cholinergic antagonist, are routinely administered before cataract surgery. What effect do these drops have on the ciliary muscle and the lens of the patient's eye?

block ciliary muscle contraction; keeps lens flat

Light rays entering the eye from a distant source are____, while light rays from near sources are _____

parallel; diverging

Ciliary muscles _____ for distant vision, and _____ for near vision.

relax, contract

The near point of vision…

1. increases with advancing age

2. changes as the lens loses its elasticity

Where is the focal point for near vision (with respect to the retina) in uncorrected presbyopia?

behind the retina

What type of lens corrects presbyopia?

convex spherical

What type of lens corrects presbyopia?

1. is part of the near response

2. involves pupillary constriction occurring simultaneously with the accommodation reflex

3. helps improve the acuity of near vision by reducing the divergent light rays from the near source

What Autonomic Nervous System activity is responsible for active pupillary dilation?

increased SANS

What Autonomic Nervous System activity is responsible for active pupillary constriction?

increased PANS

What type of muscle is found in the iris?

multi-unit smooth muscle

The convergence reflex:

1. prevents double vision

2. focuses the image on the fovea of both eyes

3. assists with near vision by moving the eyeballs inward to achieve a single image when viewing near objects

what is associated with hyperopia

1. focal point behind the retina

2. focal length >17 mm

3. refractive power of lens system

4. corrected with positive diopter lens

5. corrected with convex lens

How is correction of hyperopia accomplished?

by adding to the refractive power of the eye's refractive system therefore shortening the focal length so the focal point falls on the retina

associated with myopia

1. focal point in front of the retina

2. focal length

3. refractive power of lens system > diopters

4. corrected with negative diopter lens

5. corrected with concave lens

How is correction of myopia accomplished?

by reducing the refractive power of the eye's refractive system therefore extending the focal length so that the focal point falls on the retina

the Snellen eye chart

1. was created by Hermann Snellen, a 19th century ophthalmologist

2. sets a standard of visual acuity for people standing 20 feet from the chart.

astigmatism is the result of

a difference in refractive power in one or more axes of the refractive system

what are two potential causes of astigmatism

1. irregularly shaped cornea

2. irregularly shaped lens

If one observes an astigmatism chart and sees a blurred lines in the 2-8 axis, they can conclude:

1. they have astigmatism

2. the refraction of light in the 2-8 axis is different than in the other axes

A spherical lens has a _____focus, while the cylindrical lens has a _____ focus.

point, line

A spherical lens focuses light in _____, while the cylindrical lens focuses light in____.

all axes; one axis

A ______ can be used to correct astigmatism.

cylindrical convex lens or cylindrical concave lens