AP Biology Body Systems

Adjacent neurons with direct (non-neurotransmitter) action potential transfer are said to have electrical synapses, based on the presence of A) tight junctions at their point of contact. B) gap junctions at their point of contact. C) leaky junctions at their point of contact. D) anchoring junctions at their point of contact. E) desmosomes at their point of contact.

B

The following steps refer to various stages in transmission at a chemical synapse. 1. Neurotransmitter binds with receptors associated with the postsynaptic membrane. 2. Calcium ions rush into neuron's cytoplasm. 3. An action potential depolarizes the membrane of the axon terminal. 4. The ligand-gated ion channels open. 5. The synaptic vesicles release neurotransmitter into the synaptic cleft. Which sequence of events is correct? A) 1 → 2 → 3 → 4 → 5 B) 2 → 3 → 5 → 4 → 1 C) 3 → 2 → 5 → 1 → 4 D) 4 → 3 → 1 → 2 → 5 E) 5 → 1 → 2 → 4 → 3

C

ATP hydrolysis directly powers the movement of

Na+ out of cells

Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have

a closed circulatory system

Different body cells can respond differently to the same peptide hormones because

a target cell's response is determined by the components of its signal transduction pathways

Innate immunity is

activated immediately upon infection

In the human disease known as lupus, there is an immune reaction against a patient's own DNA from broken or dying cells, which categorizes lupus as

an autoimmune disease

In a positive-feedback system where hormone A alters the amount of protein X

an increase in A always produces an increase in X

One reason a person might be severely overweight is due to

an undersecretion of thyroxine.

The receptors on T cells and B cells bind to

antigens

Hormone X activates the cAMP second messenger system in its target cells. The greatest response by a cell would come from

applying a molecule of hormone X to the extracellular fluid surrounding the cell

All hormones

are carried to target cells in the blood

Select the pathway that would lead to the activation of cytotoxic T cells

body cell becomes infected with a virus → new viral proteins appear → class I MHC molecule-antigen complex displayed on cell surface

The body's reaction to PTH (parathyroid hormone), a reduction in plasma levels of calcium, can be opposed by

calcitonin

T cells of the immune system include

cytotoxic and helper cells

The MHC is important in a T cell's ability to

distinguish self from non-self

A chemical signal that has both endocrine and neural roles is

epinephrine

Heart rate will increase in the presence of increased

epinephrine

Dialysis patients, who will have blood withdrawn, dialyzed, then replaced, are always weighed when they enter the facility and then weighed carefully again before they leave, because

even small changes in body weight may signify changes in blood volume and therefore blood pressure `

A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin Bob), even though Jane has previously given blood for one of Bob's needed transfusions, because

even though Jane's blood type is a match to Bob's, her MHC proteins may not be a match

The meshwork that forms the fabric of a blood clot is

fibrin

Antigens are

foreign molecules that trigger the generation of antibodies

Analysis of a blood sample from a fasting individual who had not eaten for 24 hours would be expected to reveal high levels of

glucagon

Endocrine glands that are sources of steroid hormones

have a very short latency between steroid synthesis and steroid release.

Shortly after ingesting a big plate of carbohydrate-rich pasta, you measure your blood's hormone levels. What results would you expect, compared to before the meal?

high insulin, low glucagon

Oxytocin and antidiuretic hormone are synthesized in the

hypothalamus

The hypothalamus

includes neurosecretory cells that terminate in the posterior pituitary

Aspirin and ibuprofen both

inhibit the synthesis of prostaglandins.

Which hormone is incorrectly paired with its action?

insulin stimulates glycogen breakdown in the liver

Most of the neurons in the human brain are

interneurons

Prolactin stimulates mammary gland growth and development in mammals and regulates salt and water balance in freshwater fish. Many scientists think that this wide range of functions indicates that prolactin

is an evolutionarily conserved hormone

If a person loses a large amount of water in a short period of time, he or she may die from dehydration. ADH can help reduce water loss through its interaction with its target cells in the

kidney

The function of antibodies is to

mark pathogenic cells for destruction

Winter hibernation and spring reproduction in bears are cued by seasonal changes in the secretion of

melatonin from the pineal gland.

Secondary immune responses upon a second exposure to a pathogen are due to the activation of

memory cells

The increased contraction of the human uterus during labor and delivery is at least partially due to the actions of

oxytocin

Adaptive immunity depends on

pathogen- specific recognition

In a lactating mammal, the two hormones that promote milk synthesis and milk release, respectively, are

prolactin and oxytocin

Yearly vaccination of humans for influenza viruses is necessary because

rapid mutation in flu viruses alters the surface proteins in infected host cells

The operation of the sodium potassium pump moves

sodium ions out of the cell and potassium ions into the cell

Vasoconstriction in the gut is a likely response when an individual is

stressed and secreting stress hormones

The point of connection between two communicating neurons is called

synapse

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's

target cell

Fight-or-flight reactions include activation of

the adrenal medulla, leading to increased secretion of epinephrine

Melatonin is secreted by

the pineal gland during the night.

A key part of the humoral immune response is

the production of antibodies by plasma cells

When the beta cells of the pancreas release insulin into the blood

the skeletal muscles and the adipose cells take up glucose at a faster rate.

Iodine is added to table salt to help prevent deficiencies of an essential mineral needed for the proper function of the

thyroid glands.

A tropic hormone from the anterior pituitary gland regulates the secretion of

thyroxine.

Which of the following is the correct sequence of blood flow in reptiles and mammals?

vena cava, right atrium, right ventricle, pulmonary circuit