Lymphatic and Respiratory system Flashcards
Lymphatic system functions
Return lymph to the system venous system, to maintain blood volume and fluid levels and leak proteins back to the blood.
- Carry absorbed fat from the intestine to the blood
- Lymph nodes act as filters to check for foreign or pathological materials, thus fighting infection by foreign bodies via lymphocytes
Lymphatic capillaries
- Vessels that receive lymph
- Components of blood plasma filter through blood capillaries= interstitial fluid
- Lymphatic capillaries are highly permeable (more permeable than blood capillaries)
- Excess interstitial fluid flows into lymphatic capilaries
The flow of lymph is one way:
Lymphatic capillaries -> lymphatic vessels -> lymphatic trunks -> lymph ducts
Lymphoid organs
- Red bone marrow (produces lymphocytes)
Thymus (maturation of t-lymphocytes)
- A bi-lobed organ located in the anterior mediastinum
- In infants, it is quite large and extends into the superior mediastinum
- Cells of the thymus regress after puberty and it is eventually replaced by adipose connective tissue
- In adults, it atrophies and becomes almost non-functional
Spleen (monitors blood)
- A bi-lobed organ located in the anterior mediastinum
- Largest lymphatic organ located in the upper left quadrant of the abdomen
- Contains lymphocytes
- White pulp= initiates immune responses when antigens detected in blood
- Red duplex= reservoir for erythrocytes and platelets: disposes worn-out blood cells
Lymph nodes (monitors lymph, destroy pathogens)
- The lymph filters
- Organs at which the lymphatic and immune system intersect
- Location where antigens initiate an immune response (active lymphocytes)
Tonsils (destroy pathogens)
- patches of lymphatic tissue found at the entrance of the pharynx protection against ingested and inhaled pathogens
- 4 groups- palatine, lingual, pharyngeal, tubal
How do Lymphatic and CV system work together?
- Continual recycling of fluid from blood-to tissue fluid - to lymph and back to the blood
- Blood capillaries lose fluid to tissue spaces, picked up by lymphatic system, returned to blood stream
- Lymph flows from lymphatic capillaries through collective vessels, lymphatic trunks, collective ducts and is filtered through multiple lymph nodes before re-entering the bloodstream at the subclavian veins
- The lymphatic system flows at lower pressure and speed than the venous blood
- The valves of the lymphatic vessels, like those of the veins, prevent the fluid from flowing back.
Functions of the Respiratory system
Supply body with O2 and dispose of CO2
4 processes make up respiration:
- Pulmonary ventilation (breathing)
- External respiration
- Respiratory gas transport
Other important functions:
- Acid balance
- Filters and protects respiratory surfaces from pathogens and dehydration
- Vocalization
- Olfaction
Division of the Respiratory System
Functional divisions
- Conducting zone passageways that carry air to the site of gas exchange (filter, humidity, warm air)
- The respiratory zone is the site of gas exchange in the lungs
Anatomical division:
- Upper respiratory tract transports air through common structures: nose cavity, pharynx, larynx
- Lower respiratory tract transports and carries out gas exchange: trachea, bronchial tree, lungs (alveoli)
Surfactant and Nose
- Detergent-like substance that reduces the surface tension within the alveoli
- Without surfactant, the inner walls of the alveoli would stick together during exhalation
Nose - Only externally visible organ of the respiratory system
Functions - Airway for respiration
- Moistens and warms entering air filters
- Resonance chamber for speech
- Home to the olfactory receptors
Dived into external nose (bones and hyaline cartilage and internal nasal cavity.
Nasal cavity
- Air enters through external nares
- Nasal septum divides into right and left halves
- Posteriorly, continuous with the nasopharynx
- Roof formed by ethmoid and sphenoid bones
- Floor formed by palate
- Surrounded by paranasal sinuses-filter air
Lined with 2 types of mucosa membrane - Olfactory mucosa- receptor for smell
- Respiratory mucosa- epithelium with goblet cells, functions to trap inhaled debris and moisten
Lateral wall of nasal cavity
Conchae
- Bony plates found on the lateral wall of the nasal cavity that increases the surface area of the mucous membrane (superior and middle ethmoid, inferior)
- Inhalation: filter, heat and moisten air (cools conchae)
- Exhalation: cool conchae takes out moisture and extract heat back from air
- Groove inferior to each concha is a meatus
Pharynx
- Common passageway for both food and air
- Funnel-shaped passageway that connects to the nasal cavity and mouth superiorly to the larynx and oesophagus inferiorly
- Walls lined with mucosa and skeletal muscle
Divided into 3 sections - Nasopharynx: only air, uvula closes the entrance to prevent food from entering the nasal cavity, pseudostratified ciliated columnar epithelium
- Oropharynx and laryngopharynx: food and air, stratified squamous epithelium
Larynx
Connects the laryngopharynx to the trachea
- Superior ligaments: Vestibular folds: false vocal cords
- Inferior ligaments: Vocal folds, true vocal cords
- laryngeal vestibule: Above vocal cords; laryngeal ventricle- between vestibular and vocal cords (rima glottis- opening between vocal folds)
3 main functions
- Produces localizations
- Provides an open airway
- Routing air and food into proper channels (swallowing= closed, breathing= open)
Larynx cartilages
- 9 cartilages, connected by membranes and ligaments make up the larynx
1. Thyroid cartilage (Adams apple)
2. Cricoid cartilage (completes ring)
3. Arytenoid cartilage (pyramid-shaped- anchors vocal cords)
4. Corniculate cartilage
5. Cuneiform cartilage
6. Epiglottis (Elastic- keeps food out of respiratory tubes)
Trachea
- Functions: Filter, warm, humidity air
- From larynx into mediastinum, divides into 2 primary bronchi at T4 - T7
- 16-20c shaped rings of hyaline cartilage joined by connective tissue
- Trachealis muscle - contraction decreases trachea diameter
- Carina- cough reflex
- Annular ligaments connects cartilage rings
- Pseudo-stratified ciliated columnar epithelium
The Bronchial tree
- At T4-T7, the trachea branches into left and right bronchi cartilage and smooth muscle
- Primary bronchi enter the hilum of each lung with pulmonary and lymphatic vessels and nerves
Secondary/ lobar bronchi- 3 right, 2 left (each supply one lobe)
Tertiary/segmental bronchi - Changes that occur as conducting tubes become smaller:
- Cartilage is replaced with smooth muscle and elastic connective tissue
- Epithelium transitions to simple columnar and then to simple cuboidal (for gas exchange)
- No mucous of cilia in small bronchioles
The Respiratory zone
Respiratory bronchioles lead to alveolar ducts then to alveolar sacs (terminal clusters of alveoli)
- Approx 400 million alveoli allow for 140 square meters of surface area for gas exchange
- Each alveolus has 2 types of cells:
- Single layer of type 1 alveolar cells, basal lamina, and network of capillaries
- Type 2 alveolar cells produce surfactant
The lungs and pleurae
Paired lungs and pleural sacs located in the thoracic cavity
- Both lungs are conical, with concave base resting on diaphragm and blunt apex near the clavicle
- Lungs divided into loves by fissures
- Hilum on medial surface - indentation where vessels enter/exit lung
Lung anatomy
Lobes and fissures
- Left (2) - superior and inferior by oblique fissure
- Right (3) - superior, middle and inferior by oblique and horizontal fissures
Surfaces
- Mediastinal (medial, hilum)
- Diaphragmatic (base)
- Costal (made of anterior, lateral and posterior surfaces)
Borders:
- Anterior
- Posterior (smooth)
- Inferior
Diaphragm Anatomy
- Oesophageal hiatus is surrounded by muscle so during contraction of the diaphragm it is closed
- Vena cava foramen and aortic hiatus surrounded by tendons so blood can flow during contractions
Pneumothorax
When air breaks the seal of pleural fluid- lung collapses
Blood supply
Pulmonary circulation= Conducts blood from the heart to and from the gas exchange surfaces of the lungs
- Pulmonary arteries- take O2-poor blood to the lungs
- Pulmonary capillary networks- site of gas exchange alveoli
- Pulmonary veins- take O2-rich blood back to the heart
Bronchial circulation: supply the bronchi and bronchioles of the lung
Bronchial arteries branch from the anterior wall of the descending thoracic aorta and supply structures in the bronchial tree
- Larger bronchial veins collect venous blood and drain into azygos and hemizygous systems of veins
The pleurae
The serous membrane that covers the outer Lung surface and the thoracic wall, has 2 layers:
- Outer layer is the parietal pleura: covers internal surface of thoracic wall, superior surface of the diaphragm, lateral surfaces of mediastinum (sensitive to pain)
- Inner layer is the visceral pleura: covers the external lung surface (insensitive to pain)
Between these serous membranes is the pleural cavity. Membranes produce an oily, serous pleural fluid- lubricant, ensures opposing pleural membrane surface slide by each other with minimal friction during breathing
Muscles involved in ventilation
Normal inspiration (eupnea)
1. Diaphragmatic breathing (deep breathing)
- Diaphragm contracts and expands the thoracic cavity
2. Costal breathing (shallow breathing)
- External intercostals (elevate the ribs and enlarge the thoracic cavity)
Deep on forced inspiration (hyperpnea)
- Sternocleidomastoid, scalenes, pec minor quadrutus lumborum
Normal expiration can be passive- the diaphragm and/ or muscles relax
Deep or forced expiration
- Internal and external obliques, transverse abdominals (force diaphragm superiorly, depress rib cage)
- Internal intercostals and latissimus dorsi (depress rib cage)
