Reproduction

Pituitary gland

A pea-sized organ at the base of the brain, comprised of two lobes: adenohypophysis (anterior) and neurohypophysis (posterior).

Adenohypophysis

The anterior lobe of the pituitary gland, which produces six hormones including tropic hormones such as prolactin and growth hormone.

Neurohypophysis

The posterior lobe of the pituitary gland, responsible for producing antidiuretic hormone (ADH) and oxytocin.

Growth hormone (GH)

Also known as somatotropin, it promotes growth of tissues and bones, stimulating long bone growth before puberty and tissue replacement after.

Pituitary dwarfism

A condition resulting from insufficient production of growth hormone during childhood.

Gigantism

Excessive growth resulting from high levels of growth hormone in childhood.

Acromegaly

A disorder in adults caused by excess growth hormone, leading to enlargement of bones and tissues.

Gonadotropins

Hormones produced by the anterior pituitary that include luteinizing hormone (LH) and follicle-stimulating hormone (FSH), regulating sexual development.

Follicle-stimulating hormone (FSH)

Stimulates egg and sperm production in the reproductive system.

Luteinizing hormone (LH)

Stimulates the ovaries to produce testosterone and triggers ovulation.

Androgens

Male sex hormones, including testosterone, which regulate male reproductive functions.

Spermatogenesis

The process of sperm production occurring in the seminiferous tubules of the testes.

Ovaries

Female reproductive organs that produce hormones and release oocytes, essential for reproduction.

Estrogens

Primary female sex hormones that regulate reproductive organ development, body fat contour, and menstrual cycles.

Progesterone

Hormone secreted by the ovary that thickens the uterine lining and helps maintain pregnancy.

Ovulation

The release of an oocyte from an ovarian follicle, occurring approximately every 21-40 days.

Follicular phase

The first half of the menstrual cycle, during which secondary follicles mature and produce estrogen.

Luteal phase

The second half of the menstrual cycle, following ovulation, preparing the body for potential pregnancy.

Dominant follicle

The follicle that secretes high levels of estrogen and suppresses the development of other follicles during the menstrual cycle.

What is the endocrine system?

A system of glands and glandular tissues that secrete hormones into the bloodstream.

What is the master gland of the endocrine system?

The pituitary gland, which is controlled by the hypothalamus.

What are the primary glands of the endocrine system?

Pituitary gland, thyroid and parathyroid glands, adrenal glands, endocrine pancreas, and gonads (ovaries and testes).

Where are endocrine tissues found besides glands?

In organs such as the heart, stomach, intestine, kidneys, and thymus.

How are hormones secreted by endocrine glands?

Hormones are secreted into the bloodstream as needed, affecting the whole body or locally.

What type of feedback mechanisms control hormone secretion?

Many hormones are controlled through negative feedback mechanisms.

What is the variable composition of hormones?

Hormones can be proteins or chains of amino acids, or steroids which are cholesterol derivatives.