Endocrine System Overview for Anatomy and Physiology 2 Exam

Endocrine System

• Hormones are chemical messengers produced by endocrine glands to regulate various physiological processes.
• The endocrine system is a collection of glands and organs that produce hormones to regulate metabolism, growth, development, and homeostasis.
• Organs involved in the endocrine system include the thyroid, parathyroid, adrenal glands, pancreas, gonads (ovaries and testes), hypothalamus, and pituitary gland.
• Endocrine glands secrete hormones directly into the bloodstream, while exocrine glands secrete substances through ducts.

Hypothalamus and Pituitary Gland

• The hypothalamus regulates pituitary gland function through releasing and inhibiting hormones.
• The pituitary gland has two lobes: the anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis).
• The hypothalamus secretes releasing and inhibiting hormones, while the pituitary produces hormones such as GH, TSH, ACTH, FSH, LH, oxytocin, and ADH.
• The hypothalamus controls pituitary gland secretion via releasing and inhibiting hormones, forming a neuroendocrine axis.

Other Endocrine Glands

• Hormones and functions include thyroid hormones (T3 and T4), parathyroid hormone (PTH), cortisol, insulin, glucagon, estrogen, testosterone, and others.
• Hormone secretion is stimulated by hormonal, neural, or environmental cues.
• Functions of the endocrine system include regulating metabolism, calcium balance, stress response, blood glucose levels, reproductive functions, and more.

Circulatory System

• The circulatory system transports oxygen, nutrients, hormones, and waste products throughout the body.
• Components of the circulatory system include the heart, blood vessels (arteries, veins, capillaries), and blood.
• Blood composition includes plasma, red blood cells, white blood cells, and platelets.
• Physical properties of blood include viscosity, osmolarity, and pH.

Heart and Blood Vessels

• The heart is located in the thoracic cavity between the lungs and has four chambers: the right atrium, left atrium, right ventricle, and left ventricle.
• The pericardium is a double-layered sac surrounding the heart.
• Blood flow through the heart follows a specific pathway involving the pulmonary and systemic circuits.
• Valves in the heart, including the tricuspid, mitral, pulmonary, and aortic valves, prevent backflow.
• The cardiac cycle involves systole (contraction) and diastole (relaxation) phases.

Blood Circulation

• Blood pathways include the systemic circulation (body) and pulmonary circulation (lungs).
• The vascular system includes arteries, arterioles, capillaries, venules, and veins.
• Neural influences, including the sympathetic and parasympathetic nervous systems, regulate vascular function.
• Hormonal influences, including epinephrine, norepinephrine, angiotensin II, and vasopressin, also play a role.

Lymphatic and Immune Systems

• The lymphatic system has functions including fluid balance, fat absorption, and immune defense.
• Lymph formation involves fluid collected from tissues by lymphatic vessels.
• Lymphatic tissues include lymph nodes, tonsils, spleen, and thymus gland.
• The immune system has defense lines including physical barriers, innate immunity, and adaptive immunity.
• Innate immunity provides non-specific defense, while adaptive immunity provides specific defense through cellular and humoral immunity.

Respiratory System

• The respiratory system has the function of gas exchange (oxygen in, carbon dioxide out).
• Organs involved in the respiratory system include the nose, pharynx, larynx, trachea, bronchi, and lungs.
• Airflow follows a specific pathway through the respiratory system.
• Muscles involved in breathing include the diaphragm and intercostal muscles.
• Pressure gradients drive airflow.

Urinary System

• The urinary system has functions including filtration, reabsorption, secretion, and urine formation.
• Organs involved in the urinary system include the kidneys, ureters, bladder, and urethra.
• Kidney structure and function include the cortex, medulla, renal pelvis, and nephrons.
• Blood and fluid flow through the kidneys involves the renal artery, glomerulus, renal tubules, and renal pelvis.
• The filtration process involves glomerular filtration and tubular reabsorption and secretion.

Digestive System

• The digestive system has functions including ingestion, digestion, absorption, and elimination.
• Organs involved in the digestive system include the mouth, esophagus, stomach, small intestine, large intestine, liver, gallbladder, and pancreas.
• Gastric function involves epithelial cells, secretions, and production regulation.
• Hepatic and pancreatic function includes bile production, detoxification, and digestive enzyme secretion.
• Small intestine structure includes mucosa differences for increased surface area for absorption.
• Large intestine function includes water absorption, feces formation, and bacterial fermentation.