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• Hierarchical organization of body plans

  is a characteristic of all multicellular organisms.
• The form (anatomy) and biological function (physiology) of both plants and animals are correlated at all levels of organization
• Levels of organization


  • Cell
  • Tissue
  • Organ
  • Organ system
  • Organism
• Organ Systems


  Biological systems consisting of a group of organs that coordinate through a higher level of organization to perform specific functions
• Ingestion


  1. Taking in food through the mouth

  2. Feasting your eyes on the food you are about to eat serves as the visual stimulus that makes you salivate
• 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)
• Digestion


  1. Food is instantly chewed into shreds by the teeth in the oral cavity

  2. Saliva is then secreted by salivary glands mixing with the shredded food and is now termed bolus

  3. The bolus moves to the pharynx

  4. The esophagus produces contractions within its muscular wall to propel the bolus into the stomach

  5. Gastric juice helps dissolve and degrade food, particularly proteins

  6. The churning action of the stomach converts the food into a thick, liquid mixture called chyme
• Absorption and Elimination


  1. In the small intestine - fats and proteins are digested in the duodenum, food is further digested in the jejunum, and absorption of the end products of digestion takes place in the ileum

  2. Liver secretes bile to emulsify fats

  3. Gall bladder stores bile produced by the liver

  4. Pancreas secretes enzymes that breakdown major food molecules and 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, such as nutrients absorbed by digestion, wastes to be removed by the excretory system, oxygen gains through respiration and hormones secreted from the endocrine glands
• Components of the human circulatory system


  • Heart - pumps blood
  • Arteries - carry oxygenated blood away from the heart to other parts of the body
  • Veins - carry deoxygenated blood back to the heart (valves prevent blood from flowing backward)
  • Capillaries - exchange substances with nearby tissues, generally by diffusion, smallest blood vessels
  • Blood - contains RBCs, WBCs, platelets, and plasma
• Respiratory System


  Delivers oxygen to and removes carbon dioxide from the circulatory system in humans via functional units called alveoli
• Components of the Respiratory System

  • Bronchi - the main airways
  • Bronchioles - smallest airways
  • Alveoli - tiny air sacs
• Lungs provide a membrane for gaseous exchange; since they are not in direct contact with all other parts of the body, they connect to the circulatory system
• The air can then enter or leave the respiratory system through nasal cavities where air is filtered by hair and cilia, warmed by blood vessels, and humidified by mucus
• Functional units of circulatory system - alveoli
• Pathway of air in the respiratory system


  • Lungs
  • Bronchi
  • Bronchioles
  • Alveoli
• Excretory System


  Responsible for excreting metabolic wastes and aiding in the regulation of osmotic balance of blood and other body fluids
• Kidneys


  • Serve as specialized organs for osmoregulation and excretion
  • Each kidney contains millions of nephrons (functional units)
• Urine Formation


  1. Initial filtration of the blood plasma occurs in the glomerulus

  2. The glomerular filtrate is received and modified in the renal tubules

  3. Peritubular capillaries then bring substances to and take substances away from the renal tubules

  4. A collecting duct receive the processed filtrate from the renal tubule leading to the renal pelvis
• Urine Formation of Mammals

  1. Filtration starts where the blood pressure forces filtrate (water and small solutes) out of the glomerular capillaries

  2. Blood cells, proteins, and other large solutes cannot pass the capillary wall and they remain in the blood

  3. Filtrate is collected by the Bowman's capsule and funneled into the proximal tubule
• 3 main steps of urine formation


  • Glomerular filtration
  • Reabsorption
  • Secretion
• Integumentary System


  Responsible for protecting the body from mechanical injuries and infections of pathogens, preventing dehydration and regulating the body's temperature
• Layers of the Skin

  • Epidermis - the outer, thinner layer
  • Dermis - a layer of fibrous connective tissue (structures located in the dermis: sweat glands, hair follicles, and oil glands)
  • Subcutaneous layer - composed of loose connective tissue. Adipose tissue is also present in this layer
• Endocrine System


  Responsible for regulating and coordinating the body's metabolic activities and other physiological processes (glands and hormones)
• Components of the Endocrine System


  • Pineal gland
  • Hypothalamus
  • Anterior pituitary gland
  • Posterior pituitary gland
  • Thyroid gland
  • Parathyroid gland
  • Adrenal medulla
  • Adrenal cortex
  • Pancreas
  • Thymus
  • Ovaries
  • Testes
  • Lining of the small intestine/stomach
• Nervous System


  Acts as the primary regulatory system and is responsible for processing information (impulse, stimuli)
• Main Divisions of the Nervous System


  • Central nervous system (CNS) - composed of the brain and the spinal cord
  • Peripheral nervous system (PNS) - composed of nerves that branch out from the brain and the spinal cord to specific body parts
• Divisions of the Peripheral Nervous System


  • Sensory division - brings information from sense to organs to the central nervous system via afferent (incoming) neurons
  • Motor division - brings information from the brain to the body by efferent (outgoing) neurons
• Subdivisions of the Autonomic Nervous System

  • Autonomic nervous system - responsible for involuntary (without conscious effort) actions
  • Somatic nervous system - responsible for voluntary (under conscious) actions
• Muscular System


  • Allows movement of the body's organs such as the skeleton, heart, blood vessels, digestive tract, etc. work together with the skeletal system
• Muscle fibers


  The main cell type of the muscular system
• Muscle Contraction


  1. Sliding filament model revolves around the action of two proteins: actin (thin filaments) and myosin (thick filaments)

  2. When a muscle is at rest, the actin and myosin filaments are not connected to each other

  3. The action of a myosin head attaching itself to actin causes the sarcomere to contract
• Adenosine triphosphate (ATP)


  Sole fuel for muscle contraction
• Skeletal System


  Responsible for supporting and aiding the movement of the body protecting the internal organs and maintaining calcium levels
• Types of Skeletons


  • Hydrostatic skeleton - possesses no such hardened structures (earthworms)
  • Exoskeleton - is found outside the body of an organism (clams and arthropods)
  • Endoskeleton - is the opposite of the exoskeleton, which is found mostly in vertebrates, like us humans
• Parts of the Skeletal System

  • Axial Skeleton - contains the skull, ribcage and spine
  • Appendicular Skeleton - contains all the other bones
• Immune and Lymphatic System


  Act as the primary defense against different pathogens
• Types of Immunity


  • Innate or Nonspecific Immunity - the first line of defense against non-self-pathogens
  • Adaptive or Specific Immunity - only found in vertebrates, involves defenses that target specific pathogens by recognizing a specific foreign substance by its antigens and then marshaling the appropriate defenses
• Mechanisms of Adaptive Immunity


  • Humoral - attack pathogens with antibodies
  • Cellular - cell-mediated responses attack pathogens, cells infected with pathogens, and cancer cells by lysing them
• Antibodies


  Proteins produced by the immune system when it detects harmful substances