BMS 302 (Exam 2)

Increased secretion of glucagon leads to ______, which is the ______.

Gluconeogensis; formation of glucose from amino acids

Insulinoma is a disease caused by uncontrolled activity of a tumor of the beta cells in the pancreas. It results in a continuously high blood level of insulin. Which of the following physiologic findings would you expect with this disease?

Increased glycogen's and hypoglycemia.

Insulin receptors

protein molecule for insulin binding; activates glucose transporter

Glycogen

storage form of glucose; animal starch

Hypoglycemia

low blood glucose levels

Hyperglycemia

elevated blood glucose levels

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 the fasting state

Glycogenesis is a ______ process that occurs primarily ______.

synthetic; following a meal

Lipolysis is a ______ process that occurs primarily ______.

degradative; during the fasting state

Gluconeogenesis is a ______ process that occurs primarily ______.

synthetic; during the fasting state

______ reduces blood glucose levels (x2)

Glycogenesis and Lipogenesis

______ increases or returns blood glucose to the steady state level (x2)

Glycogenolysis and Gluconeogenesis

Which of the following cells require the presence of insulin before glucose can be transported across the cell membrane? (x3)

1. Muscle cells
2. Adipose tissue
3. 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 does what x4 things?

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

Which of these metabolic processes are stimulated by or require the presence of insulin?

glycogenesis and lipogenesis

Glucagon does what x3 things?

1. increases blood glucose levels
2. release is stimulated by decreased blood glucose levels
3. is released from alpha cells in the pancreas

Which of these metabolic processes are stimulated by glucagon in the liver? (x2)

glycogenolysis and gluconeogenesis

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

False

Epinephrine does what x4 things?

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

Which of these metabolic processes are stimulated by epinephrine?

glycogenolysis

Cause of hyperglycemia

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

Cause of 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

Cause of polyuria

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

Cause of polydipsia

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

Cause of 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%

Type 1 diabetes is treated with...

with insulin injections

Type 2 diabetes is usually treated with... (x2)

1. diet and exercise
2. oral medications that enhance glucose transport or increase insulin production

Diabetic coma is characterized by what? How is it treated?

too little insulin and hyperglycemia; insulin injections

Insulin shock is characterized by what? How is it treated?

too much insulin and hypoglycemia; glucagon injections and glucose

The results from glucose tolerance tests on subjects with diabetes would show (x4) things...

1. fasting glucose levels of 126 mg% or more
2. two hour post glucose load glucose levels of 200 mg% or more
3. return to fasting within 4-5 hours following glucose load
4. presence of glucose in the urine.

The results from glucose tolerance tests on subjects with NORMAL glucose control would show (x4) things...

1. fasting glucose levels of 60-110 mg%
2. two hour post glucose load glucose levels of 140 mg% or less
3. return to fasting within 2-3 hours following glucose load
4. absence of glucose in the urine

T/F: The American Diabetes Association recommends that all adults are screened for diabetes by the time they are 45 years of age.

True

T/F: Screening tests should be done every 3 years.

True

T/F: 16 million people in the US have diabetes and don't know.

False

T/F: A diagnosis of diabetes can be made if the fasting blood glucose is >126 mg%

True

T/F: Glucose levels can be as high as 150 mg% two hours after a glucose load and still be considered normal.

True

Use the DuBois Body Surface Area Nomogram in your manual to determine a subject's body surface area if their height is 150 centimeters and weight is 55 kilograms. Calculate to the nearest 1/10.

1.5

A diabetic coma patient needs to be treated sucessfully with an insulin dose rate of 0.5 units/kg of body weight. She currently weighs 55 kilograms and the insulin you have available has a concentration of 60 units/milliliter. Calculate how much you need to inject to treat her. Your answer should be rounded to the nearest 1/100th.

0.46

Your subject has a body surface area of 1.9 meters2. The lab manual instructs you to give the subject 40 grams of glucose per m2 of surface area. If the glucose solution has 10 grams of glucose per ounce, how many ounces does your subject need to ingest for the Glucose Tolerance Test? Calculate answers to nearest 1/10.

7.6

When reporting blood glucose levels units may be in x3:

1. mg/100 ml
2. mg/dl
3. mg%

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 does what x4 things?

1. provides the area of greatest acuity.
2. It's where we direct our focus when trying to view an object.
3. It's the area where the four layers of accessory neurons and blood vessels are pulled "to the side".
4. It allows light to directly stimulate the cones.

The site where the optic nerve and blood vessels leave the retina...(x2)

is the blind spot and has no photoreceptors.

What two factors determine the refractive power of a lens?

1. The angle at which light enters a lens.
2. The difference in the refractive indices of the two media (air:aqueous solution, air:glass, aqueous solution:glass, water:aqueous solution, etc.)

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

1. cornea
2. lens
3. aqueous humor
4. 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

the point at which light converges behind the lens

focal length

distance between the focal point and the lens

convex lens

lens that causes light rays to converge

concave lens

lens that causes light rays to diverge

Regarding concave vs convex, which terms are grouped together appropriately?

1. concave, diverging, negative diopter
2. convex, converging, positive diopter

If a lens has a refractive power of of + 57 diopters, its focal length would be____ meters.
Note: calculate and round to the nearest 1/1000 meters.

0.018

Which of the following are associated with emmetropia? x3

1. Focal point on the retina
2. Focal length = 17 mm
3. Refractive power of lens system = 59 diopters

What three reflexes are associated with the near response?

1. accommodation reflex
2. pupillary reflex
3. convergence reflex

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

increases

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... (x2)

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

The pupillary reflex has what x3 characteristics...?

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 does what x3 things?

1. assists with near vision by moving the eyeballs inward to achieve a single image when viewing near objects.
2. focuses the image on the fovea of both eyes.
3. prevents double vision.

Which x5 characteristics are 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

Which x5 characteristics are associated with myopia?

1. Focal point in front of the retina
2. Focal length
3. Refractive power of lens system >59 diopters
4. Corrected with concave lens
5. Corrected with negative diopter 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... x2

Was created by Hermann Snellen, a 19th century ophthalmologist and sets a standard of visual acuity for people standing 20 feet from the chart.

20/20:

normal vision acuity; standing 20 feet away

20/10:

better than normal acuity; subject sees at 20 feet what someone with 20/20 could see at 10 feet

20/200:

poor vision acuity; subject sees at 20 feet what someone with 20/20 could see at 200 feet

Astigmatism is a 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:

They have astigmatism and 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

all axes; one axis

A ______ can be used to correct astigmatism.

cylindrical convex lens and cylindrical concave lens

Which of the following statements concerning contact lenses is/are true?

1. Hard, but not standard soft contact lenses be used to correct astigmatism.
2. The tear layer between a hard lens and a cornea with an irregular surface helps correct the refractive defects.
3. A special soft lens called toric lenses can be used for astigmatic eyes.

Correct sequence of wave of depolarization that passes through the heart is:
1 = atrioventricular (AV) node
2 = sinoatrial (SA) node
3 = Purkinje fibers
4 = bundle of His
5 = bundle branches

2,1,4,5,3...

2 = sinoatrial (SA) node
1 = atrioventricular (AV) node
4 = bundle of His
5 = bundle branches
3 = Purkinje fibers