General Biology 2

• Organ systems - biological systems consisting of a group of organs that coordinate through a higher level of organization to perform specific functions
• hierarchical organization (smallest to highest)

  cell - tissue - organ - organ system - organism
• ingestion - process of taking in food through the mouth
• 2 types of digestion

  chemical - involves the action of enzymes and other chemical substances in the body.

  mechanical – involves the cutting, crushing or grinding the food using the teeth (mastication).
• bolus - mixing with the shredded food
• digestive system - ingestion, digestion, absorption and elimination
• chyme - helps in converting the food into a thick, liquid mixture
• 3 regions of the small intestine - duodenum, jejunum, ileum
• accessory organs:

  liver - responsible for the secretion of bile to emulsify fats

  gal bladder - stores bile produced by the liver

  pancreas - responsible for the secretion pf enzymes that breakdown major food molecules. Produces insulin hormone for the control of glucose metabolism
• circulatory system - makes it possible for the movement of prime substances from one part of the body to another
• component of circulatory system

  heart - pumps blood

  arteries - caries oxygenated blood

  veins - carries deoxygenated blood

  capillaries - exchange substances with nearby tissues, generally by diffusion, smallest blood vessels
• respiratory system - responsible for gas exchange
• bronchi - main airways
• bronchioles - smallest airway
• Functional units of circulatory system alveoli - Lungs – Bronchi – Bronchioles - alveoli
• excretory system - excreting metabolic waste
• urine formation

  initial filtration of the blood plasma occurs in the glomerulus

  is received and modified in the renal tubules

  Peritubular capillaries then bring substances to and take substances away

  A collecting duct receive the processed filtrate from the renal tubule leading to the renal pelvis
• 3 main steps of urine formation

  1) glomerular filtration

  2) reabsorption

  3) secretion
• integumentary system - protects the body from the environment and regulates body temperature
• layers of the skin: epidermis, dermis, subcutaneous layer
• endocrine system - responsible for regulating and coordinating the body's metabolic activities and other physiological processes
• Endocrine glands are ductless and release their secretions directly into your bloodstream.
• Exocrine glands have ducts and release their secretions onto your body's surfaces or into your body’s cavities
• A gland is any organ that secretes substances
• Pineal gland regulates biological rhythms.
• Hypothalamus - regulates the pituitary gland.
• Anterior pituitary gland regulates growth and metabolism, activities of the gonads, thyroid gland, adrenal cortex, and mammary glands
• Posterior pituitary gland - responsible for uterine contractions, lactation, and water movement of body parts and the reabsorption in the kidneys
• Thyroid gland regulates metabolism through several means and decreases calcium levels in the blood
• Parathyroid gland raises calcium levels in the blood
• Adrenal medulla initiates "fight or flight" response during times of acute stress
• Adrenal cortex - raises glucose levels in the blood and regulates ion reabsorption excretion in kidneys
• Pancreas - regulates blood glucose level
• Thymus - responsible for T-cell development (used in the immune system).
• Ovaries - in charge of the growth of the uterine lining and maintenance of secondary sex characteristics
• Testes - responsible for sperm formation and maintenance of secondary sex characteristics
• Lining of the small intestine/stomach stimulates the small intestine/stomach to release enzymes
• nervous system - primary regulatory system and is responsible for processing information (impulse, stimuli)
• main divisions of nervous system

  central nervous system - composed of the brain and the spinal cord

  peripheral nervous system - composed of nerves that branch out from the brain and the spinal cord to specific body parts.
• sensory division - brings information from sense to organs to the central nervous system via afferent (incoming) neurons.