Histology #4 (Respitory) Flashcards
Functions of Respitory system
- Gas exchange (Main function)
- Regulates blood pH
- Sense of smell
- Phonation
- Air filtration
- Extretes watere and heart
Respitory = works closley with the cardiovascular system
- Respitory = Gas exchnage
- Cardiovascular = distrubutes O2 throughout the body and collects CO2 from the tissues
Divisions of Respitory system
Structural divisions - Upper vs. Lower Respitory
- Upper - Nose + Nasal cavity + Oral Cavity + Pharynx
- Lower - Trachea + Primary Bronchi + Lungs + Larynx
Functional dividions - Conducting vs. Respitory
- Conducting -
- Respitory - Respitry bronchials + Aveoli Ducts + Aveolar sacs
Lungs and Tracheobronchial Tree
Lung Plura
Covering of the lungs - Plura
- Composed of Visceral and Parietal Plura (between the two have the Plura space filled with fluid)
Image - see visceral plura on inside + parietal plura on outside
Visceral Plura
Layer that intimatley covers the lungs (wraps around all of the fissues on the lung surface)
- Wraps the lungs
- Closer to lung parachyma
Function - Sceretes plueral fluid –> fluid reduces friction as the lungs expand
Dividied into 5 Layers:
Mesothelial (most superficial) –> Submesothelial –> External elastic –> Interstitial –> Internal Elatic
- Interstial layer contains capilaries and lymphatics
Image - see the 5 layers
Visceral Plura (Images)
Right - HPS stain –> college is stained yellow/orange + see the lymphatic system in the middle
- Astrics = show the lymphatic system
Parietal Plura
Layer that lines the chest wall and covers the diaphram and mediastinum
- Outter layer
- Runs paraell to the chest
Function - Protection (Very fiberous -> provides support to the lung structure)
Consists of 5 Layers:
Mesothelial (outtermost) –> Subesothelia –> Fibradipose –> Interstitial –> Internal Elastic
- Interstitial layer = has collegen fibers
Image - See adipose cells in teh Fibroadipose layer
Parietal Plura (Images)
Right - Top most layer = mesothelial layer THEN the lower layers is connective tissue THEn have adipose cells
Left - See the collegen organization
Lung Lobule
Overall - Fundemental respitory unit of the lungs (functional unit)
- Plura = covers and prtects the lung lobules
Function - Gas exchnage
Made up of 10-30 Acini
- Acini = Composed of Alveolar Ducts + Aveolar Sacs + Aveoli
Relationship between lung lobule and pluera
Each lobule lies beneath the visceral plura
- Plura = supports the expansion and contraction of the lung lobule
- Plura = close to the parachyma – have blood vessles going through + have plura fluid in the plura cavity which provides cushioning for aveoli
The plural fluid in the cavity between the visceral and parietal pleura ensure that each lobule expands and contracts without friction or resistence
Trachea + Brinchi
Trachea + Bronchi = forms the tracheobronchi tree (part of the conducting zone)
Trachea = moves air from nose and mouth to the lungs
Bronchi = disrtubutes air to the lobes of the lungs
Layers of the walls of Trachea and Bronchi
Mucosa –> Submucosa –> Cartilagenous layer –> Adventitia
Mucosa - innermost layer lines with epithelia cells (contains goblet and basal cells)
Submucosa - connective tissue suporting the mucosa
- Helps with conrtraction
Cartilagenous layer - cartileganois rings and intervening smooth muscle
- Smooth muscle = structrual support
- Function - structural support and integrity
Adventitia - More internal fibroelastic layer of connective tissue
- Function - connects submucosa to other tissue
Mucosa layer specific to bronchi
In the muscosa layer. have part that is ONLY found in Bronchi –> have a layer of muscle cels that move mucosa
Muscle cells = also help constrict and dilate during breath
Trachea Epithelia cells
Psudostratified epithelum line trachea (cilated + has goblet cells + basal cells)
- Cilia help move the muscus to the Pharynx
- basal cells line under the psudostratified epithelum
- basal cells = stem cells –> differeniate into epitheliam cells
Mucous = traps dust (first line of defense) + moisturizes the air + brings the air to the right temperature
Bronchi Epithelia cells
Psudostratified epithelium (cilitaed + has goblet and basal cells)
Image - see the goblet cels (Cicular sacs)
Submucosal glands and ducts
Overall - Secretory structure found in submucosa that line cartilagenous airways
Location - Larynx + trachea + primary bronchi
Function - Defends against inhaled and exhaled pathogens
- Have water + ions + proteins accuminated in colecting ducts)
- Ciliated region at the top = connects to epithelial surface = moves things to the epithelial layer
- Has a role in innate immunity
- Physically secreates pathogens to move out of lungs
Strcuture – tubuloacinar secrtroy rehions joined by ducts (See sceretrtor regiion at the botted and collecting duct cells in green fiurther up)
- Connected ducts are at the to
What happens if have issue in submcosal ducts
Have issue in submucosal ducts = get cystic fibrosis
Submucosal glands and ducts (histology)
Left - in trachea - see it boarders cartilegenous layer + closer to the surface
Cartilage rings
Overall - C shaped rings composed of hyaline cartiage
Location - Trachea
Structure - 16-20 C shaped rings that line the entire length of the trachea
- NOT fully round (connected at the posterior end by smooth muscle)
- Smooth muscle = near the asphogus (sophage needs to be able to move to transport food.= have soft tissue in back of trachea)
Function - Support the trachea and allow it to move and flex without collapse while breathing
Cartilage plates
Overall - Hyline cartilege structures located within bronchial walls
Location - Bronchi
- In the Primary bronchi here are still cartilagnous rings BUT in the secondary bronchi the rings become cresent shaped plates or islands
Function - Keeps the airway open and the bronchi from collapsing during inhilation and exhalation
Structure - Cresent shaped plates or islands
Image -
Bottom - see irregularly shaped plates + has smooth msucle at the bottom
Top - see cartilege lining top of bronchi + smooth muscle
Adventitia
Overall - most superfivial layer of the trachea and the bronchi
Structure - Loose connectve tissue (collegen)
Function - anchors the trachea and bronchi to adjacent tissues
- Provides elastcity + strength + support
- Allows for seperation between structures (important because trachea and brocnhi are part of conducting system = don’t want things to come in)
Adventitia (Trachea histology)
Right - see loos arangment of fibers in adventia
Left - Adventitia anchors the trachea + loos arangments allows the trachea to expand
Adventitia (Bronchi histology)
See similar to trachea
Bronchioles
First structure in the respitory portion
Function - Direct air movement into aveoli
- Also block and clear debris + secret proteins to protect epithelium + degrade airborn toxins + regerate epithelum
Contains ciloated and non ciliated columnar and cuboidal cels + contain clara cells (non-ciliated)
Contains smooth msucle cells and elastic fibers –> allows for dontraction and dilation to control airflow
Does NOT contain cartilege and glands (as oppose to bronchi that do)
Images:
Top left - clara cells
Bottom Left and right - cross sectio of bronchiooles (see smooth muscle cells around epithelium –> controls air flow)
Clara cells
Non ciliated dome cells –> improtant for secreting proteins + creating epithelium + maintain bronchioles
Types of bronchioels
- Terminal brocnhioles
- Respitory bronchioles
Branching Function – increases surface area = optimizes gas exhnage + decreases air veolicty as air flows through
Image - se the terminal bronchiols branch into the respitory
Terminal bronchioles
Most distal conducting airways
Each branch of Terminal bronchiole gives rise to 2-5 respotroy bronchioles (terminal bronchioles branch into respitory bronchioles)
Resptory Bronchioles
Intial airways into where gas exchnage ahppens
Contains Alveoli (allows for gas exchnage to occur)