Respiratory System Department of Histology and Embryology Yu hongwei
When blood glucose drops, the __________ releases _________ which travels to the _________ causing __________ breakdown to release glucose into the bloodstream. A) pancreas; insulin; muscles; proteinB) pancreas; glucagon; liver; glycogenC) liver; insulin; pancreas; glycogenD) liver; glucagon; pancreas; lipid
All of these are functions of the liver EXCEPT: • A) biotransformation of molecules. • B) production of digestive enzymes. • C) storage of glycogen, fat, vitamins, and iron. • D) synthesis of bile. • E) synthesis of blood components.
Respiratory System • Nasal cavity • The pharynx • The larynx • The trachea , bronchi • The lung
Respiratory System • Conducting portion • Respiratory portion
Conducting portion Nasal cavity, nasopharynx, larynx, trachea , bronchi, bronchioles and terminal bronchioles Function: Condition the inspired air(cleaned,moistened, warmed)
Respiratory portion Respiratory bronchioles,alveolar duct, alveolar sac,and alveoli. Function:Gas exchange
Nasal cavity Ep:stratified squamous ep(Vibrissae) LP:sebaceous and sweat gland vestibular region respiratory region olfactory region Ep: pseudostratified ciliated columnar ep. LP:vascular network Olfactory cells Supporting cells Basal cells Ep:olfactory ep. LP:serous gland(Bowman gland)
Trachea • Structure: • Mucosa: • Submucosa • Adventitia
Epithelium Pseudostratified ciliated columnar epithelium • Ciliated cell • Goblet cell • Brush cell • Basal cell • small granule cell
Epithelium Figure 17-6: Ciliated respiratory epithelium
Ciliated cell • They cells with cilia which project from the apical surface. • The cilia provide a coordinate sweeping motion from the farthest reaches towards larynx.
Epithelium Goblet cell • They can synthesize and secrete mucus. • The secretion covers the epithelium surface. Brush cell: they are columnar cells that bear blunt microvilli.
A ciliated mucous lining in the nose and pharynx, and the cilia-mucus elevator in the trachea, defend against microbial by trapping foreign particles in inspired air.
Many fire survivors who have inhaled large amounts of smoke – get the protective cilia layer damaged because of extreme dryness. • As a result, the cilia can no longer effectively “beat” out the mucus and, together with the debris, the lungs get flooded with mucus. • Many of those smoke-injured fire survivors later die from pneumonia complications.
Basal cell: It is stem cell. • Small granule cell: They are difficult to distinguish from basal cells in the light microscope.With the TEM,the cytoplasm contains many granules.
Submucosa • LCT containing mixed glands. • Serous glands that keep the epithelium moist;and mucous glands that provide a covering in which dust particles get caught.
Adventitia • LCT containing "C" shaped hyaline cartilage and smooth muscles. • Hyaline cartilage provides a supporting structure that prevent collapse of the tracheal lumen during expiration. • The gaps between the cartilages ends are filled in by smooth muscles.
Trachea - Structure • Walls contain 16-20 “C” shaped rings of hyaline cartilage
Asthma • Asthma is a serious disease that affects the lungs and the airways that deliver air to the lungs.
Allergy--"the epidemic of the 21st century". • Allergy is the leading cause of asthma. It causes periodic attacks of wheezing and difficult breathing. • The airways may become blocked when the muscles surrounding the lungs tighten. Or, mucus may narrow the airways in the lungs, making breathing even more difficult.
Lung • Parenchyma • Bronchial tree • Alveolus • Mesenchyme:CT
Changes of conduction portion • The cartilages become irregular,and are progessively smaller. • The amount of muscle in the bronchial wall increase. • Glands become fewer,and are absent in the bronchioles. • The epithelium become thinner.
Clara cells Terminal bronchiole lined by simple ciliated columnar cells. Cells that are found among ciliated columnar cells, are non-ciliated and contain rich secretory granules. Function:Protection against harmful substance; Stem cell function.
Respiratory portion Function: Capable of air exchange. • Respiratory bronchiole: the wall is populated with more and more alveoli. • Alveolar duct:They have almost no walls,only alveoli,as their boundary. • Alveolar sac: They shared opening of several surrounding alveoli. • Alveoli: Terminal blind ends of the track. The main place where the air exchanges occur.
Respiratory bronchiole Alveolar duct Alveolar sac Alveoli
Alveoli Epithelium • type I cells: squamous, cover 95% of the alveolar surface. • type II cells : Secrotory cells. contain multilamellar bodies, which are capable to release the surfactant to lower the surface tension. A surfactant can greatly reduce the surface tension . • Can differentiate into Type I cells.
Epithelium of Alveoli Type Ⅰalveolar cell Type Ⅱalveolar cell
2. Alveolar septum: Thin layer of LCT between adjacent alveoli. Continuous Caps: The richest Cap network in the body. Abundant elastic and reticular fibers: Function when alveoli are enlarged. • 3. Alveolar pores: Windows between the adjacent alveoli that can equalize the air pressure. • 4.Blood-air barrier
Emphysema • causes a loss of elasticity in the walls of the small air sacs in your lungs. When emphysema is advanced, you must work so hard to expel air from your lungs. Treatments focus on relieving symptoms.
4.Blood-air barrier • surfactant ,type I cells and basal lamina, LCT, capillary endothelium and basal lamina