HAPS Exam A&P2

What is the primary function of the endocrine system?

To regulate body functions through hormones released into the bloodstream.

What is a hormone?

A chemical messenger secreted by endocrine glands that acts on target cells.

What is the difference between the endocrine and nervous systems?

The endocrine system acts more slowly but has longer-lasting effects, while the nervous system acts rapidly with short-lived effects.

What is an endocrine gland?

A ductless gland that secretes hormones directly into the blood.

What is a target cell?

A cell that has receptors for a specific hormone.

Why can only target cells respond to a hormone?

Because only they possess the appropriate receptors.

What are the two major classes of hormones?

Steroid hormones and amino acid-based hormones.

Which hormones can pass directly through the plasma membrane?

Steroid hormones.

Where are steroid hormone receptors usually located?

Inside the cell, in the cytoplasm or nucleus.

Where are receptors for amino acid-based hormones usually located?

On the plasma membrane.

What are the three mechanisms that regulate hormone secretion?

Humoral, neural, and hormonal stimuli.

What is humoral stimulation?

Hormone release triggered by changes in blood levels of ions or nutrients.

What is neural stimulation?

Hormone release triggered by nerve impulses.

What is hormonal stimulation?

Hormone release triggered by another hormone.

How are most hormone levels regulated?

Through negative feedback.

Why is the hypothalamus considered the link between the nervous and endocrine systems?

Because it controls the pituitary gland using both neural signals and hormones.

What is the pituitary gland often called?

The master gland.

What are the two lobes of the pituitary gland?

Anterior pituitary and posterior pituitary.

Does the posterior pituitary produce hormones?

No. It stores and releases hormones produced by the hypothalamus.

Which hormones are released from the posterior pituitary?

Antidiuretic hormone (ADH) and oxytocin.

What is the function of growth hormone (GH)?

Stimulates body growth, protein synthesis, and cell division.

What condition results from excess growth hormone during childhood?

Gigantism.

What condition results from growth hormone deficiency during childhood?

Pituitary dwarfism.

What condition results from excess growth hormone in adults?

Acromegaly.

What is the function of thyroid-stimulating hormone (TSH)?

Stimulates the thyroid gland to release thyroid hormones.

What is the function of adrenocorticotropic hormone (ACTH)?

Stimulates the adrenal cortex to release cortisol.

What is the function of follicle-stimulating hormone (FSH)?

Stimulates gamete production in the ovaries and testes.

What is the function of luteinizing hormone (LH)?

Triggers ovulation in females and testosterone production in males.

What is the function of prolactin?

Stimulates milk production after childbirth.

What is the function of oxytocin?

Stimulates uterine contractions and milk ejection.

Where is the thyroid gland located?

Anterior to the trachea just below the larynx.

What hormones are produced by the thyroid gland?

Triiodothyronine (T3), thyroxine (T4), and calcitonin.

What is the primary function of T3 and T4?

Increase metabolic rate.

Why is iodine necessary for thyroid hormone production?

It is required to synthesize T3 and T4.

What is hypothyroidism?

A condition in which the thyroid produces too little thyroid hormone.

What is hyperthyroidism?

A condition in which the thyroid produces excessive thyroid hormone.

What hormone lowers blood calcium levels?

Calcitonin.

Which glands produce parathyroid hormone (PTH)?

The parathyroid glands.

What is the primary function of parathyroid hormone (PTH)?

To increase blood calcium levels.

Which hormone plays the greater role in calcium regulation in adults?

Parathyroid hormone (PTH).

What are the two regions of the adrenal gland?

The adrenal cortex and adrenal medulla.

Which hormone is released by the adrenal medulla during the fight-or-flight response?

Epinephrine.

What is the primary glucocorticoid released by the adrenal cortex?

Cortisol.

What is the primary function of cortisol?

Increase blood glucose and help the body respond to long-term stress.

What hormone promotes sodium and water retention by the kidneys?

Aldosterone.

Which pancreatic cells produce insulin?

Beta (β) cells.

Which pancreatic cells produce glucagon?

Alpha (α) cells.

What is the function of insulin?

Lower blood glucose by promoting glucose uptake into cells.

What is the function of glucagon?

Raise blood glucose by stimulating glycogen breakdown and glucose production.

What hormone is released by the pineal gland?

Melatonin, which regulates circadian rhythms and the sleep-wake cycle.

What are the formed elements of blood?

Erythrocytes, leukocytes, and platelets.

What is plasma?

The liquid portion of blood composed mostly of water, proteins, electrolytes, nutrients, hormones, and wastes.

What percentage of blood is plasma?

About 55%.

What percentage of blood is formed elements?

About 45%.

What is the primary function of erythrocytes (red blood cells)?

To transport oxygen and carbon dioxide.

What protein allows red blood cells to carry oxygen?

Hemoglobin.

Where are red blood cells produced?

In the red bone marrow.

What hormone stimulates red blood cell production?

Erythropoietin (EPO).

Where is erythropoietin produced?

Primarily by the kidneys.

What is the average lifespan of a red blood cell?

About 120 days.

What is hematocrit?

The percentage of blood volume occupied by red blood cells.

What is anemia?

A condition characterized by a reduced oxygen-carrying capacity of the blood.

What is polycythemia?

An abnormal increase in the number of red blood cells.

What is the primary function of leukocytes (white blood cells)?

To protect the body against infection and disease.

What are the five types of leukocytes?

Neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Which white blood cell is the most abundant?

Neutrophils.

Which white blood cells produce antibodies?

B lymphocytes.

Which white blood cells directly attack infected cells?

T lymphocytes.

Which white blood cells become macrophages in tissues?

Monocytes.

Which white blood cells increase during allergic reactions and parasitic infections?

Eosinophils.

Which white blood cells release histamine during inflammation?

Basophils.

What are platelets?

Cell fragments involved in blood clotting.

What is hemostasis?

The process that stops bleeding.

What are the three stages of hemostasis?

Vascular spasm, platelet plug formation, and coagulation.

What is coagulation?

The formation of a fibrin clot to stabilize the platelet plug.

What protein forms the meshwork of a blood clot?

Fibrin.

What vitamin is required for normal blood clotting?

Vitamin K.

What is a thrombus?

A blood clot that forms within an intact blood vessel.

What is an embolus?

A clot or other material that travels through the bloodstream and blocks a vessel.

What are the four major blood types in the ABO system?

A, B, AB, and O.

Which blood type is considered the universal donor for red blood cells?

O negative.

Which blood type is considered the universal recipient for red blood cells?

AB positive.

What determines a person's ABO blood type?

The presence or absence of A and B antigens on red blood cells.

What determines whether a person is Rh positive or Rh negative?

The presence or absence of the Rh (D) antigen.

Where is the heart located?

In the mediastinum between the lungs.

What is the function of the heart?

To pump blood through the pulmonary and systemic circulations.

What are the four chambers of the heart?

Right atrium, right ventricle, left atrium, and left ventricle.

Which side of the heart pumps blood to the lungs?

The right side.

Which side of the heart pumps blood to the body?

The left side.

Which chamber has the thickest wall?

The left ventricle.

Why is the left ventricle thicker than the right ventricle?

It must generate greater pressure to pump blood throughout the body.

What valve separates the right atrium and right ventricle?

The tricuspid valve.

What valve separates the left atrium and left ventricle?

The bicuspid (mitral) valve.

What valve lies between the right ventricle and pulmonary trunk?

The pulmonary semilunar valve.

What valve lies between the left ventricle and aorta?

The aortic semilunar valve.

What is the function of the heart valves?

To prevent the backflow of blood.

What is the myocardium?

The muscular middle layer of the heart responsible for contraction.

What is the endocardium?

The inner lining of the heart chambers and valves.

What is the pericardium?

The sac that surrounds and protects the heart.

What is the cardiac conduction system?

The specialized tissue that generates and conducts electrical impulses through the heart.