Endocrine System Overview

Endocrine System

• Six hypothalamic hormones regulate the anterior pituitary:

  • GnRH: Stimulates gonadotropin release (FSH, LH)
  • TRH: Stimulates thyroid-stimulating hormone (TSH) release
  • CRH: Stimulates adrenocorticotropic hormone (ACTH) release
  • GHRH: Stimulates growth hormone (GH) release
  • PIH: Inhibits prolactin release
  • Somatostatin: Inhibits release of GH and TSH

• Two hypothalamic hormones are stored in the posterior pituitary and released on demand:

  • Oxytocin (OT): Stimulates labor contractions and milk release
  • Antidiuretic hormone (ADH): Stimulates water retention by the kidneys

Anterior Pituitary

• Synthesizes and secretes six major hormones:
  • FSH: Stimulates ovarian sex hormone secretion and ovarian development
  • LH: Stimulates ovulation, progesterone secretion, and testosterone secretion

Other Hormones

• Thyroid-stimulating hormone (TSH): Stimulates thyroid hormone (TH) release
• Adrenocorticotropic hormone (ACTH): Stimulates adrenal cortex to secrete glucocorticoids
• Prolactin (PRL): Stimulates mammary glands to synthesize milk after birth
• Growth hormone (GH): Stimulates mitosis and cellular differentiation

Blood

• Four components:
  • Erythrocytes (red blood cells)
  • Platelets (fragments of bone marrow cells)
  • Leukocytes (white blood cells): Granulocytes (neutrophils, eosinophils, basophils) and Agranulocytes (lymphocytes, monocytes)
• Adults contain 4-6 liters of blood

Blood Types

• Antigens are complex molecules on cell membranes
• Agglutinogens trigger agglutination (clumping)
• Antibodies bind to antigens, marking them for destruction
• Agglutination occurs when antibodies bind to multiple foreign antigens

Blood Vessel Anatomy

• Three categories: arteries, veins, capillaries

• Healthy blood pressure for young adults is 120/75 mmHg

• Hypertension (high blood pressure) can weaken arteries and cause aneurysms

• Lymphatic system function: filtration, immunity production, fluid return to bloodstream, and lymph drainage.

• Lymph nodes are bean-shaped structures that cleanse lymph and are sites of lymphocyte activation.

Respiratory System Functionality

• Inhalation/exhalation of air; gas exchange
• Communication (speech, vocalizations)
• Olfaction (sense of smell)
• Acid-base balance (influences pH of body fluids)
• Blood pressure regulation (assists with hormone synthesis)
• Blood and lymph flow (breathing creates pressure gradients)

Respiratory Volumes

• Tidal volume (TV): Volume of air inhaled and exhaled in a single breathing cycle
• Inspiratory reserve volume (IRV): Air in excess of tidal volume that can be inhaled
• Expiratory reserve volume (ERV): Air in excess of tidal volume that can be exhaled
• Residual volume (RV): Air remaining in the lungs after maximum exhalation

Digestive System

• Five stages of digestion:

  • Ingestion: Selective intake of food
  • Digestion: Mechanical and chemical breakdown of food
  • Absorption: Uptake of nutrient molecules into the epithelial cells
  • Compaction: Absorbing water to consolidate wastes
  • Defecation: Elimination of feces

• Peristalsis: Waves of involuntary contractions coordinated by the swallowing center and the myenteric plexus.

Urinary System Anatomy

• Renal corpuscle consists of the glomerulus and a Bowman's (glomerular) capsule
• Vascular pole: where afferent and efferent arterioles enter/exit the corpuscle
• Urinary pole: where renal tubule begins
• Mesangial cells: pack the spaces between the glomerulus and the tubule

Male Reproductive System

• Vas deferens are manipulated during a vasectomy.
• Sperm mature in the epididymis.
• Sperm structure includes a head (nucleus and acrosome), midpiece (mitochondria), and tail (flagellum).

Female Reproductive System

• Ovulation: Release of a mature egg from the ovary; Fertilization: union of a sperm with an egg in the fallopian tube; implantation: attachment of fertilized egg to the uterine lining; Menstruation: shedding of the uterine lining if fertilization does not occur.

Additional Information

• Natural killer (NK) cells continually patrol the body to detect pathogens; attack and destroy microbes, transplanted cells, cells infected with viruses, cancer cells.
• Forms of Adaptive immunity: Natural active immunity, Artificial active immunity, Natural passive immunity, Artificial passive immunity.
• Hormones involved in regulating the reproductive and endocrine systems (FSH, LH, GnRH, estrogen, progesterone etc)

Test your knowledge on the key hormones of the endocrine system, including those regulated by the hypothalamus and secreted by the pituitary gland. This quiz covers important functions and roles of hormones like GnRH, TSH, and oxytocin. Perfect for students studying human biology or related fields.