Exam 1 bio 202

What is an endocrine gland?

A ductless gland that releases hormones into the bloodstream.

What is an exocrine gland?

A gland that releases substances through ducts onto a surface or into a body cavity.

What is the main difference between endocrine and exocrine glands?

Endocrine = hormones into blood; Exocrine = secretions through ducts.

How does neural control differ from hormonal control?

Neural control uses electrical impulses and is rapid; hormonal control uses hormones in blood and is slower.

What are the major endocrine organs?

Hypothalamus, pituitary gland, thyroid, parathyroid glands, adrenal glands, pancreas, pineal gland, thymus, ovaries, testes.

Where is the pituitary gland located?

At the base of the brain, just below the hypothalamus.

Where is the thyroid gland located?

In the front of the neck, below the larynx.

Where are the adrenal glands located?

On top of the kidneys.

Where is the pancreas located?

Behind the stomach.

How are most hormones regulated?

Through negative feedback, where the hormone's effects reduce the original stimulus for hormone release.

What is negative feedback?

A response that reduces or reverses the original stimulus.

What is positive feedback?

A response that increases the original stimulus.

What is the relationship between the hypothalamus and pituitary gland?

The hypothalamus controls the pituitary and links the nervous system to the endocrine system.

What does the anterior pituitary produce?

GH, TSH, ACTH, FSH, LH, and prolactin.

What hormones are released by the posterior pituitary?

ADH and oxytocin.

Where are ADH and oxytocin actually produced?

They are produced by the hypothalamus and stored/released by the posterior pituitary.

What does ADH do?

It helps the kidneys retain water, helping regulate blood volume and blood pressure.

What does oxytocin do?

It stimulates uterine contractions and milk ejection.

What are the two major chemical categories of hormones?

Steroid and nonsteroid hormones.

What are steroid hormones made from?

Cholesterol.

Can steroid hormones cross the cell membrane?

Yes, they are lipid-soluble and can cross the membrane.

Where do steroid hormones bind to receptors?

Inside the cell, usually in the cytoplasm or nucleus.

Can nonsteroid hormones cross the cell membrane easily?

No, they usually bind to receptors on the cell membrane.

What is a second messenger?

A molecule inside a cell that carries a hormone's signal from a membrane receptor to the inside of the cell.

What is a circulating hormone?

A hormone that enters the bloodstream and travels to distant target cells.

What is a local hormone?

A hormone that acts near the site where it was released.

What is a paracrine?

A local chemical messenger that acts on nearby cells.

What is an autocrine?

A chemical messenger that acts on the same cell that released it.

What hormones does the thyroid produce?

T3 and T4 and calcitonin.

What do T3 and T4 do?

They increase metabolic activity and are important for growth and development.

What does calcitonin do?

It helps lower blood calcium levels.

What does PTH do?

Parathyroid hormone raises blood calcium levels.

What hormones are produced by the adrenal cortex?

Aldosterone, cortisol, and adrenal androgens.

What does aldosterone do?

It promotes sodium and water retention and helps regulate blood pressure.

What does cortisol do?

It helps the body respond to stress and affects metabolism and blood glucose.

What hormones are produced by the adrenal medulla?

Epinephrine and norepinephrine.

What do epinephrine and norepinephrine do?

They help produce the fight-or-flight response, including increased heart rate.

What does insulin do?

Lowers blood glucose by helping cells take up glucose.

What does glucagon do?

Raises blood glucose by stimulating glucose release into the blood.

What hormones do the ovaries produce?

Primarily estrogen and progesterone.

What hormone do the testes primarily produce?

Testosterone.

What does the pineal gland produce?

Melatonin.

What does melatonin help regulate?

The sleep-wake/circadian rhythm.

What is the function of the thymus?

It produces hormones involved in T-cell development and immune function.

How does aging affect the endocrine system?

Hormone production and sensitivity to some hormones can change, affecting metabolism, reproduction, glucose regulation, and stress responses.

What is extracellular fluid?

Fluid located outside cells.

What are the two major extracellular fluid compartments?

Plasma and interstitial fluid.

What is whole blood made of?

Plasma and formed elements.

What are the formed elements of blood?

Red blood cells, white blood cells, and platelets.

Why is blood classified as connective tissue?

Because it consists of cells suspended in an extracellular matrix, which is plasma.

What is plasma?

The fluid portion of blood.

What is plasma mostly made of?

Mostly water, plus proteins, electrolytes, nutrients, hormones, gases, and wastes.

What are the three major plasma proteins?

Albumin, globulins, and fibrinogen.

What does albumin do?

Helps maintain osmotic pressure and fluid balance.

What does fibrinogen do?

It is important for blood clotting.

What is the main function of erythrocytes?

To transport oxygen and carbon dioxide.

What protein allows RBCs to carry oxygen?

Hemoglobin.

What is the shape of an RBC?

A biconcave disc.

Why is the biconcave shape useful?

It provides a large surface area for gas exchange and helps the cell remain flexible.

Do mature RBCs have a nucleus?

No.

What is hematopoiesis?

The process of blood cell production.

Where does hematopoiesis primarily occur?

In red bone marrow.

What is the main function of leukocytes?

Defense and immunity.

What are the five major types of WBCs?

Neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Which WBC is most abundant?

Neutrophils.

What do neutrophils do?

They primarily perform phagocytosis, especially against bacteria.

What do lymphocytes do?

They are important for immune responses.

What do monocytes become when they enter tissues?

They can become macrophages.

What are eosinophils associated with?

Parasites and allergic reactions.

What are basophils associated with?

Inflammation and histamine release.

What are platelets?

Small cell fragments involved in blood clotting.

Where do platelets come from?

They are fragments of megakaryocytes in bone marrow.

What is hemostasis?

The process of stopping bleeding.

What are the three major steps of hemostasis?

Vascular spasm → platelet plug formation → coagulation.

What happens during vascular spasm?

The damaged blood vessel constricts.

What happens during platelet plug formation?

Platelets stick to the damaged area and each other, forming a temporary plug.

What happens during coagulation?

A series of reactions produces fibrin, which strengthens the clot.

What is the difference between the intrinsic and extrinsic pathways?

The intrinsic pathway is activated by factors within the blood; the extrinsic pathway is triggered by tissue damage.

What determines ABO blood type?

The presence or absence of A and B antigens on RBCs.

What antigens does type A blood have?

A antigens.

What antibodies does type A have?

Anti-B antibodies.

What antigens does type B have?

B antigens.

What antibodies does type B have?

Anti-A antibodies.

What antigens does type AB have?

A and B antigens.

What antibodies does type AB have?

Neither anti-A nor anti-B.

What antigens does type O have?

Neither A nor B antigens.

What antibodies does type O have?

Anti-A and anti-B.

What is anemia?

A condition involving too few RBCs or inadequate hemoglobin, reducing oxygen-carrying capacity.

What is leukemia?

A cancer involving blood-forming tissues and abnormal production of blood cells, especially WBCs.

What is thrombocytopenia?

An abnormally low platelet count, which can increase bleeding risk.

What is hemophilia?

An inherited disorder involving deficient clotting factors that causes impaired clotting.

Where is the heart located?

In the mediastinum, between the lungs.

What direction does the apex of the heart point?

Downward and toward the left.

What is the pericardium?

A protective sac surrounding the heart.

What is the function of pericardial fluid?

It reduces friction as the heart beats.

What does the right atrium receive?

Deoxygenated blood from the superior vena cava, inferior vena cava, and coronary sinus.

What does the right ventricle do?

Pumps deoxygenated blood to the lungs.

What does the left atrium receive?

Oxygenated blood from the pulmonary veins.

What does the left ventricle do?

Pumps oxygenated blood to the body through the aorta.

Which chamber has the thickest wall?

The left ventricle, because it pumps blood through the entire systemic circuit.