15-16

• Process

  1. ventilation and breathing

  2. Exchange of O2 and CO2 between air in the lungs and the blood

  3. Transport of O2 and CO2 in the blood

  4. Exchange of O2 and CO2 between blood and tissues
• Functions of the respiratory system

  • Respiration
  • Regulation of Blood pH
  • Voice Production
  • Olfaction
  • Innate Immunity
• Nose

  • External Nose composed of hyaline cartilage
  • Nasal cavity extends from nostrils to choane, hard palate is its roof
  • Choana openings to pharynx
  • Paranasal sinuses are air filled spaces within the bone, open into the nasal cavity, lined with mucous
  • Conchae on each side of the nasal cavity increase the surface area, help in cleaning, humidifying, and warming of air
  • Nasolacrimal Ducts carry tears from eyes, open into nasal cavity
• Functions of the Nose

  • Airways for respiration
  • Filter
  • Involved in speech
  • Olfactory Receptors
  • Sneezing dislodges materials from the nose
  • Warms air
• Pharynx


  • Common passageway for the respiratory and digestive systems
• Trachea


  • Windpipe
  • Consists of 16-20 C-shaped pieces of cartilage
  • Contains cilia pseudostratified columnar epithelium
  • Divides into right and left primary bronchi
  • Cilia line the primary bronchus to remove microbes and debris from the interior of the lungs
• Bronchi


  • Divide from trachea
  • Connect to lungs
  • Lined with cilia
  • Contain C-shaped pieces of cartilage
• Lungs


  • Primary organ of respiration
  • Cone shaped
  • Base rests on the diaphragm
  • Apex extends above the clavicle
  • Right lung has 3 lobes, left lung has 2 lobes
  • Contains many air passageways
• Lung Airway Passages

  • Primary Bronchi
  • Lobar bronchi
  • Segmental Bronchi
  • Bronchioles
  • Terminal Bronchioles
  • Respiratory Bronchioles
  • Alveolar ducts
  • Alveoli
• Alveoli


  Small air sacs where gas exchange occurs, surrounded by capillaries, 300M in lungs
• Asthma Attack


  Contraction of terminal bronchioles leads to reduced air flow
• Pleural Membrane and cavities

  • Pleura is a double-layered membrane around lungs
  • Parietal Pleura is the membrane that lines the thoracic cavity
  • Visceral Pleura is the membrane that covers the lung's surface
  • Pleural cavity is the space around each lung
• Ventilation (Breathing)


  1. Inspiration - breathe in, uses the diaphragm and the external intercostal muscles, diaphragm descends and rib cage expands, thoracic cavity volume increases, pressure decreases, atmospheric pressure, air moves into alveoli

  2. Expiration - breathe out, uses the diaphragm, diaphragm relaxes and rib cage recoils, thoracic cavity volume decreases, pressure increases, alveolar pressure > atmospheric pressure, air moves out of lungs

  3. Forceful expiration uses internal intercostal muscles
• Lung Recoil


  Tendency for an expanded lung to decrease in size, during quiet expiration
• Surfactant


  Mixture of lipoproteins produced by secretory cells of the alveoli, single fluid layer on the surface of thin fluid lining alveoli, keeps lungs from collapsing
• Factors that Influence Pulmonary Ventilation

  • Lung elasticity
  • Lung compliance
  • Respiratory passageway resistance
• Pulmonary volumes

  • Tidal volume (TV)
  • Inspiratory reserve volume (IRV)
  • Expiratory reserve volume (ERV)
  • Residual Volume (RV)
  • Vital capacity (VC)
• Respiratory Membrane


  Where gas exchange between blood and air occurs
• Partial Pressure


  Pressure exerted by a specific gas in a mixture
• Components of the Gastrointestinal Tract

  • Mouth
  • Pharynx
  • Esophagus
  • Stomach
  • Small intestines
  • Large intestines
  • Rectum
  • Anus
• Associated organs of the Digestive System

  • Salivary glands
  • Liver
  • Gallbladder
  • Pancreas
• Layers of Digestive Tract Wall (Tunics)

  • Mucosa - inner most layer secretes mucus
  • Submucosa - above mucosa contains blood vessels nerve and small glands
  • Muscularis - above mucosa longitudinal circular and oblique muscles
  • Serosa/Adventitia - outermost layer. with peritoneum is serosa, without peritoneum adventitia
• Peritoneum


  • Smooth epithelial tissue
  • Mesenteries are connective tissue of organs in the abdominal cavity
  • Lesser Omentum is a mesentery connecting lesser curvature of the stomach to the liver and diaphragm
  • Greater Omentum is a mesentery connecting greater curvature of the stomach to transverse colon and posterior body wall
• Oral Cavity


  • First part of the digestive system
• Salivary Enzymes


  • Amylase
  • Lysozyme
• Tongue


  • Houses taste buds and mucus
• Teeth

  • 32 (adult), 20 (baby teeth)
  • Pulp cavity is the center of the tooth
  • Enamel is the hard covering that protects against abrasions
  • Cavities are the breakdown of enamel by acids from bacteria
• Palate


  • Hard Palate is the anterior part, Soft Palate is the posterior part
• Pharynx


  • Throat connects the mouth to esophagus
• Esophagus


  • Connects the pharynx to the stomach
• Stomach


  • Located in the abdomen
  • Storage tank for food
  • Contains a thick mucus layer that lubricates and protects epithelial cells on stomach wall
  • Forms acidic pH (3)
  • Has 3 muscular layers: outer longitudinal, middle circular, inner oblique
  • Rugae are large folds that allow the stomach to stretch
• Chyme


  Paste-like substance that forms when food begins to be broken down
• Pyloric opening


  • Opening between stomach and small intestine
• Pyloric Sphincter


  Thick ring of smooth muscle around the pyloric opening
• Hunger pangs


  Stomach is stimulated to contract by low blood glucose levels usually 12-24 hours after a meal
• Regulation of Stomach and secretions

  1. Cephalic Phase - Stomach secretion are initiated when bolus stimulates receptors in the oropharynx

  2. Gastric Phase - partially digested proteins and distention of stomach promote secretion

  3. Intestinal phase - acidic chyme stimulates neuronal reflexes and secretions of hormones that inhibit gastric secretions by negative feedback loops
• Movement in Stomach

  1. Mixing waves - weak contraction that thoroughly mix food to form Chyme

  2. Peristaltic waves - stronger contraction that force chyme toward and through pyloric sphincter
• Small Intestine


  • 6m in length, major absorptive organ
  • Parts: Duodenum, Jejunum, Ileum
• Duodenum


  • 25 cm long, contains absorptive cells, goblet cells, granular cells, endocrine cells, contain microvili, many folds, bile, and pancreatic ducts
• Cystic Duct


  Joins common hepatic duct from gallbladder