ANSC 220 Lecture 14 - Endocrine IV and the Cardiovascular System

Vocabulary practice flashcards covering endocrine axes (thyroid, parathyroid, adrenal) and the anatomy and functional mechanisms of the mammalian cardiovascular system.

Thermogenesis

Heat production in the body, which is stimulated by thyroid hormones ($T_3$ and $T_4$) alongside increases in metabolic rate and energy expenditure.

Hypothyroidism

A condition characterized by a reduction or loss of thyroid hormone production by the thyroid gland, causing symptoms such as increased sensitivity to cold, abnormal adiposity, depression, and impaired memory.

Goiter

An abnormal enlargement of the thyroid gland, most commonly caused worldwide by iodine deficiency or inflammation of the thyroid gland.

Hashimoto’s thyroiditis

An autoimmune disease in humans where the immune system attacks thyroglobulin, leading to inflammation and swelling of the thyroid gland.

Follicle colloid

The central luminal substance within thyroid follicles that serves as the specific location of $T_3$ and $T_4$ synthesis.

Parathyroid Chief cells

Endocrine cells within the parathyroid gland that detect low blood calcium and respond by secreting parathyroid hormone (PTH).

Parathyroid Hormone (PTH)

A hormone not regulated by the hypothalamus or pituitary that raises blood calcium by increasing osteoclast activity, releasing calcium and phosphate from bone, and increasing kidney vitamin D production.

C cells (parafollicular cells)

Cells located in the thyroid gland that release calcitonin when calcium levels become optimal, thereby inhibiting osteoclast activity.

Nutritional hyperparathyroidism

Abnormal concentrations of PTH in the blood caused by reduced calcium in the diet or reduced calcium absorption from the digestive tract, leading to bone degeneration, deformities, osteoporosis, or rickets.

Bran disease (Bighead or Miller’s disease)

A form of nutritional hyperparathyroidism occurring in horses that results in bone degeneration, deformities, and characteristic enlargement of the facial bones.

Corticotropin releasing hormone (CRH)

A neuroendocrine hormone synthesized by the paraventricular nucleus (PVN) of the hypothalamus that stimulates ACTH secretion from anterior pituitary corticotropes.

Adrenocorticotropic hormone (ACTH)

A hormone secreted by corticotropes of the anterior pituitary that stimulates the adrenal cortex to produce and release cortisol.

Zona glomerulosa

The outermost zone of the adrenal cortex that synthesizes and secretes mineralocorticoids, primarily aldosterone.

Zona fasciculata

The intermediate layer of the adrenal cortex containing ACTH receptors that produces glucocorticoids, specifically cortisol, in response to ACTH stimulation.

Zona reticularis

The innermost layer of the adrenal cortex that produces androgens, including androstenedione.

Adrenal medulla

The inner core region of the adrenal gland surrounded by the cortex that synthesizes and releases catecholamines (epinephrine and norepinephrine).

Cortisol

A steroid hormone that binds glucocorticoid receptors to stimulate hepatic gluconeogenesis and glycogenolysis, adipose lipolysis, and muscle proteolysis, while suppressing digestion, immunity, and reproduction.

Hans Selye

The researcher known as 'The Father of Stress Physiology' who demonstrated that pathological damage often results from the body's reaction to stress.

Cardiovascular system

An organ system composed of the heart (kardia/cardio) and small vessels (vasculature) that transports substances under pressure throughout the body.

Mediastinum

The central compartment of the thoracic cavity that encloses the pericardial cavity and the heart.

Pericardial cavity

The fluid-filled space situated between the visceral pericardium and parietal pericardium surrounding the heart.

Pulmonary circulation

The vascular circuit powered by the right pump of the heart that delivers oxygen-depleted blood to the lungs for gas exchange.

Systemic circulation

The high-pressure vascular circuit powered by the left pump of the heart that delivers oxygen-rich blood to the tissues of the body.

Veins

Vessels that carry blood toward the heart chambers regardless of oxygen saturation level.

Arteries

Vessels that carry blood away from the heart chambers regardless of oxygen saturation level.

Right atrioventricular (AV) valve

A tricuspid cardiac valve that ensures unidirectional blood flow from the right atrium into the right ventricle.

Left atrioventricular (AV) valve

A bicuspid or mitral cardiac valve consisting of two leaflets that ensures unidirectional blood flow from the left atrium into the left ventricle.

Chordae tendineae

Tendinous cords anchored by papillary muscles that attach to AV valve margins, preventing their leaflets from everting back into the atria during ventricular contraction.

Semilunar valves

Pocket-like, three-cusp valves (the aortic and pulmonary valves) that prevent backflow of blood from the great arteries into the ventricles during ventricular relaxation.