Hormones and the Endocrine System

Jul 26, 2024

Review flashcards

Hormones and the Endocrine System

Overview

  • Body produces 50 different hormones.
  • Regulate functions like growth, development, mood, sleep, hunger, reproduction, metabolism.
  • Keep body in homeostasis.

Major Endocrine Glands

  1. Brain Glands:
    • Hypothalamus
    • Pituitary Gland (Anterior and Posterior)
    • Pineal Gland
  2. Neck Glands:
    • Thyroid Gland
    • Parathyroid Glands (Two pairs)
  3. Other Glands:
    • Adrenal Glands (On top of kidneys)
    • Pancreas (Behind stomach)
    • Gonads (Testes in males, ovaries in females)

Brain Glands and Their Hormones

Hypothalamus

  • Signals brain and body
  • Master Gland along with anterior pituitary

Pituitary Gland

Anterior Pituitary

  • Growth Hormone (GH): Affects growth of organs, bones, cartilage.
  • Prolactin: Responsible for lactation, breast development in females.
  • Thyroid-Stimulating Hormone (TSH): Stimulates thyroid to produce hormones.
  • Adrenocorticotropic Hormone (ACTH): Stimulates adrenal glands.
  • Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH): Stimulate gonads to secrete sex hormones (estrogen, progesterone, testosterone); regulate menstrual cycle.
  • Controlled by hypothalamus.

Posterior Pituitary

  • Antidiuretic Hormone (Vasopressin): Controls blood pressure via salt and water balance.
  • Oxytocin: Stimulates uterine contractions in childbirth; "love hormone."
  • Hypothalamus produces hormones, transports them via neurons.

Pineal Gland

  • Produces Melatonin: Helps regulate sleep cycles.

Thyroid and Parathyroid Glands

Thyroid Gland

  • Produces Thyroid Hormone (Thyroxine T4):
    • Increases basal metabolism.
    • Converted to Triiodothyronine (T3) at target cell.
    • T3 is more active than T4.
    • Iodine is essential.
  • Produces Calcitonin: Decreases calcium levels in blood.

Parathyroid Glands

  • Produce Parathyroid Hormone (PTH): Increases calcium levels in blood.
  • Regulates calcium for bones, muscle contraction, blood clotting.

Pancreas

  • Insulin: Lowers blood glucose by enabling cell intake of glucose.
  • Glucagon: Raises blood glucose by releasing stored glucose in the liver.
  • Imbalance leads to diabetes (Type 1 and Type 2).

Adrenal Glands

Adrenal Cortex

  • Produce Glucocorticoids (e.g., Cortisol): Regulate metabolism, inflammation, immune function.
  • Produce Mineralocorticoids (e.g., Aldosterone): Regulate minerals like sodium, potassium, affecting blood pressure.
  • Produce small amounts of Androgens: Sex hormones aiding in reproduction.

Adrenal Medulla

  • Secretes Adrenaline and Epinephrine, Noradrenaline and Norepinephrine: Initiate fight-or-flight response.

Gonads

Testes (Males)

  • Produce Testosterone: Affects sperm production.

Ovaries (Females)

  • Produce Estrogen and Progesterone: Regulate menstrual cycle, reproductive functions.

Interactions and Feedback

  • Hormones can impact each other (e.g., insulin, cortisol, thyroid hormone).
  • Kidney-produced Renin regulates blood pressure and interacts with adrenal hormones.
  • Supported by nervous system and environmental cues.

Summary

  • Hormones maintain balance and coordinate body activity.
  • Everyone is hormonal all the time, not just teenagers.