Human Anatomy and Physiology: Endocrine, Respiratory, Digestive, Urinary, and Reproductive Systems

A comprehensive set of vocabulary flashcards covering the anatomy and physiology of the endocrine, respiratory, digestive, urinary, and reproductive systems based on lecture notes.

Hormones

Chemicals released by the endocrine system that leave a gland or gland-like structure to maintain homeostasis by changing the rate of physiological activities of cells.

Exocrine glands

Glands that release products through ducts into specific areas.

Endocrine glands

Ductless glands that release products directly into the blood.

Hypophysis

Another name for the pituitary gland, which is attached to the hypothalamus via the infundibulum and sits in the sella turcica (hypophyseal fossa).

Adenohypophysis

The anterior lobe of the pituitary gland, divided into regions: pars tuberalis, pars intermedia, and pars distalis.

Thyroid follicles

Structures consisting of simple cuboidal epithelium around a follicle cavity filled with colloid, a protein-rich viscous fluid.

C-thyrocytes

Cells in the thyroid gland responsible for calcitonin production, which helps regulate calcium and phosphate levels.

Zona glomerulosa

The upper or superficial zone of the adrenal cortex.

Alpha cells

Pancreatic islet cells that produce glucagon for glycogen breakdown.

Beta cells

Pancreatic islet cells that produce insulin to increase cellular glucose uptake.

Melatonin

The substance synthesized by the pineal gland, which contains special secretory cells called pinealocytes.

Pulmonary ventilation

The process of respiration involving inspiration (inhalation) and expiration (exhalation).

External (pulmonary) respiration

The exchange of gases between the lungs and the blood where oxygen diffuses into the blood and $CO_2$ diffuses out.

Internal (tissue) respiration

The exchange of gases between the blood and cells where oxygen is delivered to cells and $CO_2$ diffuses into the blood.

Respiratory epithelium

A lining consisting of pseudostratified ciliated columnar cells and mucus-producing cells, except in the pharynx, smaller bronchi, and alveoli.

Larynx

A cylinder with cartilaginous walls stabilized by ligaments and skeletal muscles that serves as the main divider for the sense of smell and contains the glottis.

Type II alveolar cells

Cells scattered among Type I cells that secrete surfactant to prevent alveolar collapse.

Blood air barrier

A three-layered structure where gas exchange occurs, consisting of the alveolar cell layer, capillary endothelium, and a fused basement membrane.

Mucosa

The inner lining of the digestive tract consisting of epithelium, lamina propria, and muscularis mucosae.

Muscularis externa

The layer of the digestive tract surrounding the submucosa, containing internal circular fibers and outer longitudinal fibers that facilitate peristalsis and segmentation.

Peritoneum

The largest serous membrane of the body, consisting of simple squamous epithelium (mesothelium) and connective tissue.

Mastication

The process of mechanical digestion in the oral cavity that forms a bolus.

Deglutition

The process of swallowing, divided into buccal, pharyngeal, and esophageal phases.

Chyme

The viscous, acidic fluid consisting of gastric juices and partly digested food that passes from the stomach to the small intestine.

Parietal cells

Stomach cells that secrete intrinsic factor (for $B_{12}$ absorption) and hydrochloric acid ($HCl$).

Chief cells

Stomach cells that secrete pepsinogen, rennin, and gastric lipase.

Hepatocytes

Liver cells arranged in plates around a central vein that produce bile.

Kupffer's cells

Stellate macrophages located in the liver sinusoids that act as phagocytic cells to eat debris or toxins.

Calcitriol

The active form of Vitamin $D$ synthesized by the kidneys to aid in calcium absorption.

Nephron

The basic functional unit of the kidney, with approximately $1.25 \times 10^6$ per kidney, responsible for filtering blood.

Glomerulus

A network of fenestrated capillaries within the renal corpuscle where filtration occurs to produce a protein-free solution.

Podocytes

Specialized cells that forms the glomerular epithelium of the renal corpuscle.

Trigone

The triangular area of the urinary bladder where the ureteral orifices enter.

Spermatogenesis

The process of sperm development via meiosis occurring in the seminiferous tubules of the testes.

Acrosome

A cap on the head of a spermatozoon containing enzymes like hyaluronidase, which are necessary for fertilization of the egg.

Seminal glands

Glands that produce approximately $60\text{\%}$ of semen volume, including a high concentration of fructose.

Oogenesis

The process of female gamete production, which begins before birth.

Corpus luteum

The structure formed from an empty follicle after ovulation that produces progesterone to prepare the body for pregnancy.

Endometrium

The inner mucosal layer of the uterine wall that thickens during the uterine cycle and sheds during menstruation if no egg implantation occurs.

Lactiferous ducts

Ducts in the mammary glands that lead from the lobes to the nipple to transport milk.