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
