Endocrine System Overview

Posterior Pituitary Gland Role

• The posterior pituitary gland acts as a storage and release site for hormones synthesized by the hypothalamus.

Thyroid Gland Regulation

• Thyroid-stimulating hormone (TSH) from the anterior pituitary gland regulates the function of the thyroid gland.

Growth Hormone Excess

• Excess growth hormone (GH) in the body can lead to gigantism in children and acromegaly in adults, causing abnormal growth in bones, hands, feet, and facial features.

Hypothalamus-Anterior Pituitary Interaction

• The hypothalamus influences the anterior pituitary gland through releasing and inhibiting hormones. These hormones travel through the hypophyseal portal system, regulating the secretion of hormones from the anterior pituitary.

Goiter Cause

• An abnormal increase in thyroid-stimulating hormone (TSH) can lead to a goiter, an enlargement of the thyroid gland.

Hypothalamus-Posterior Pituitary Relationship

• The hypothalamus produces hormones (ADH and oxytocin) that are stored and released by the posterior pituitary, making it an extension of the hypothalamus.

Hypothyroidism Cause

• Insufficient thyroid-stimulating hormone (TSH) levels can lead to hypothyroidism, a condition characterized by a low metabolic rate, fatigue, and weight gain.

Growth Hormone Function

• Growth hormone (GH), primarily produced by the anterior pituitary, stimulates growth in bones, muscles, and organs.

Antidiuretic Hormone (ADH) Function

• Antidiuretic hormone (ADH) promotes water reabsorption in the kidneys, regulating blood volume and concentration.

Antidiuretic Hormone (ADH) Abnormality

• Diabetes insipidus, a disorder characterized by excessive urination and dehydration, results from insufficient ADH production or impaired response to ADH.

Labor Hormone

• Oxytocin, released from the posterior pituitary, triggers and strengthens uterine contractions during labor.

Calcitonin Target Tissue

• Bone tissue is the target for calcitonin, a hormone produced by the thyroid gland that lowers blood calcium levels.

Iodine Requirement

• The thyroid gland requires iodine to synthesize thyroid hormones, which are essential for regulating metabolism.

Thyroid Hormone Effects

• Thyroid hormone influences metabolic rate, body temperature regulation, growth and development, and heart function.

Anterior-Posterior Pituitary Difference

• The anterior pituitary gland produces its own hormones, while the posterior pituitary stores and releases hormones made by the hypothalamus.

Follicular Cell Secretion

• Follicular cells of the thyroid gland primarily secrete thyroxine (T4) and triiodothyronine (T3), the main hormones produced by the thyroid.

Hypothalamus-Posterior Pituitary Role

• The hypothalamus synthesizes and transports hormones (ADH and oxytocin) to be stored and released by the posterior pituitary.

Releasing Hormones Function

• Releasing hormones from the hypothalamus stimulate the secretion of specific hormones from the anterior pituitary.

Inhibiting Hormones Function

• Inhibiting hormones from the hypothalamus suppress the secretion of specific hormones from the anterior pituitary.

Anterior Pituitary Function

• The anterior pituitary gland plays a key role in regulating growth, metabolism, and reproduction through the secretion of various hormones.

Hypothalamus-Anterior Pituitary Interaction

• The hypothalamus controls the anterior pituitary through releasing and inhibiting hormones that travel through the hypophyseal portal system.

Hypothalamus-Anterior Pituitary Relationship

• The hypothalamus-anterior pituitary relationship is characterized by a complex feedback loop where releasing and inhibiting hormones from the hypothalamus regulate the release of hormones from the anterior pituitary.

Inhibiting Hormone Effect

• When an inhibiting hormone is released by the hypothalamus, it reduces the secretion of specific hormones from the anterior pituitary.

Anterior-Posterior Pituitary Distinction

• The anterior pituitary is an endocrine gland that produces its own hormones, while the posterior pituitary is an extension of the hypothalamus that stores and releases hormones synthesized by the hypothalamus.

Releasing Hormones Effect

• Releasing hormones stimulate the production and release of specific hormones from the anterior pituitary gland, regulating various bodily functions.