new exam material Flashcards
What are the functions of the respiratory system
- air conduction
- air conditioning
- gas exchange (respiration)
- speech- larynx
- olfaction- olfactory mucosa
- endocrine- hormone production and secretion
- immune function- BALT
what is the conducting portion of the respiratory system
a series of air passages between the atmosphere and the lungs
what is the respiratory portion of the respiratory system
the parenchyma of the lungs where the gas exchange actually occurs
what are the parts of the conducting portion of the respiratory system
- nasal cavity
- paranasal sinuses
- pharynx
- larynx
- trachea
- bronchi
- terminal bronchioles
what are the bronchi
a series of hollow tubes in the lungs that branch into increasingly smaller tubes. splits from
main (primary) bronchi- one for each lung
lobar (secondary) bronchi- one for each lobe of the lung
segmental (tertiary) bronchi- several branches
…. 12 hierarchies until bronchioles
what are the terminal bronchioles
the smallest (in caliber) structures of the conducting portion of the respiratory system
what are the parts of the respiratory portion of the respiratory system
respiratory bronchioles
alveolar ducts
alveolar sacs
alveoli- the site of the vast majority of the gas exchange!
what is the main site of gas exchange
alveoli
what is the boarder of the upper and lower respiratory tract
the upper respiratory tract down to and includes the larynx
the lower starts at the trachea lungs and respiratory tree (bronchi and branches)
what lines the conducting portion of the respiratory system
an epithelium known as respiratory epithelium
respiratory epithelium
a special type of epithelium that lines the conducting portion of the respiratory system. it is a CILIATED PSEUDOSTRATIFIED COLUMNAR epithelium
what are the five types of cells found in the respiratory epithelium
- ciliated columnar cells
- goblet cells
- brush cells
- small granule cells
5 basal cells
what is the most abundant type of cell in the respiratory epithelium
the ciliated columnar cells, they extend the full thickness of the epithelium
what are cilia, and their arrangement
hair like structures on the apical domain of cells. they are composed of microtubules with a 9+2 arrangement. they are attached to a basal body in which the microtubules are arranged in a 9+3 arrangement. they are motile structures
mucociliary escalator
made of many cilia that work together to sweep mucus on the suface of the epithelium out towards the external surface ofr the body
what are goblet cells
unicellular glands that extend the full thickness of the epitheium and produce mucus that forms a thick layer on the surface oft eh epithelium in the respiratory system
brush cells
extend the full thickness of the epithelium and have microvilli at their apical domain. these microvilli are made of microfilaments. in the basal domain of the brush cells there is a synaptic contact with an afferent nerve ending making brush cells receptors for touch in the respiratory epithelium. they begin the afferent limbs of the cough and sneeze reflexes
small granule cells
do NOT extend the full thickness of the epithelium. they are filled with membrane- bound vesicles. they are part of the enteroendocrine system and secrete a variety of hormones to control enteric systems.
basal cells
do NOT extend the full thickness of the respiratory epithelium. they are the shortest cells and their nuclei are closest to the basal lamina of the epithelium. they are generative cells and can form all the other types of cells in the epithelium
generative cells
undergo mitosis, the basal cells are generative cells that form all the other types of cells in the epithelium
what are the parts of the nasal cavity
- vestibule
2. respiratory segment
what is the vestibule of the nasal cavity
the anterior dilated portion that communicates with the external environment through the nostrils. its distal portion is covered by skin with vibrissae which filter out large particles. the proximal portion is lined with respiratory epithelium. the most distal portion is keratinized stratified squamous epithelium
vibrissae
short thick hairs in the vestibule of the nasal cavity that filter out large particles from the air.
what epithelium is associated with the vestibule of the nasal cavity
keratinized stratifed squamous in the distal portion
respiratory epithelium in the proximal portion
what is the respiratory segment of the nasal cavity
the majority of the nasal cavity. lined with respiratory epithelium, on top of the lamina propria (thin loose connective tissue). contains diffuse lymphatic tissue
lamina propria
in the nasal cavity it is a thin layer of loose connective tissue with seromucous glands that secrete mucus layer of the surface of the epithelium. it has a superficial venous plexus that warms the incoming air. also contains diffuse lymphatic tissue
respiratory mucosa
the mucous membrane made up of respiratory epithelium and lamina propria
what is deep to the lamina propria
periosteum of the bone lining the nasal cavity
how does the respiratory segment communicate of the nasal cavity communicate with the nasopharynx
choanae (which are the internal nares)
olfactory segment of the nasal cavity
relatively small region in the roof of the nasal cavity sensitive to odor.
what epithelium is associated with the olfactory segment
pseudostratified columnar epithelium known as the olfactory epitheliium
cells associated with the olfactory epithelium
- olfactory receptor cells
- sustentacular (supporting) cells
- basal cells
what are olfactory (receptor) cells’ characteristics?
they extend the full thickness of the epithelium with nuclei at multiple intermediate depths. they are bipolar neurons- dendrites act as non motile cilia and olfactory receptors. they are unmyelinated and run through the cribiform plate of the ethmoid bone. axons are collectively known as the olfactory nerve
characteristics of sustentacular (supporting cells) in olfactory segment
extend full thickness of the epithelium. nuclei closes to the epithelium. function similar to glial cells as they support olfactory receptor cells
characteristics of basal cells in olfactory segement
nuclei closest to basal lamina and do not extend the full thickenss of the epithelium. they are mitotic cells and form new supporting cells
which cells in the olfactory epithelium span the full thickness of the epithelium?
olfactory cells, sustentacular cells
why is it important that the olfactory glands have a constant flow?
to “wash out” the surface of the epithelium for new smells
what does the lamina propria attach to
periosteum of the ethmoid bone and the olfactory epithelium
what type of gland is the olfactory gland?
branched tubuloalveolar serous
whats the difference between serous and mucous
serous is more watery
what is the solvent for odiferous molecules
serous production from the olfactory glands of the bowmans
what are the paranasal sinuses
extension of the nasal cavity into surrounding bones with relatively narrow connections to the nasal cavity
what bones have paranasal sinuses
frontal
ethmoid
maxillary
sphenoid
why are sinuses prone to infection
because they have narrow connections to the rest of the nasal cavity, often a secondary infection to a more generalized upper respiratory infection
what lines the paranasal sinuses?
respiratory epithelium and a very thing lamina propria (loose connective tissue layer)
What is the pharynx?
musculomembranous passage that connects the nasal and oral cavities to the larynx and esophagus
what are the parts of the pharynx
- nasopharynx
- oropharynx
- laryngopharynx
characteristics nasopharynx
lined with respiratory epithelium and lamina propria, it is in the region above the soft palate. includes openings for the auditory (Eustachian) tube and pharyngeal tonsil (adenoids)
characteristics of oropharynx
region below the soft palate and above the epiglottis. it is lined with tratified squamous non-keratonized epithelium and a thin lamina propria
characteristics of laryngopharynx
region at the level of the epiglottis. lined with stratificed squamous non-keratonized epithelium and lamina propria
what is the mucous membrane?
epithelium and lamina propria
what is the larynx? characteristics and functions
musculocartilaginous structure lined with mucous membrane that connects the pharynx to the trachea. it is a passage way for air in and out of the trachea and closes off the trachea when swallowing to prevent food in the trachea. also involved in phonation- making sound
what lines the larynx
respiratory epithelium
what lines the epiglottis and vocal folds?
stratified non-keratonized epithelium
where does the lamina propria not have seromucous glands in the larynx?
in the vocal folds
what cartilages are associated with the lamina propria in the larynx?
- thyroid
- cricoid
- epiglottic
what type of cartilage is the thyroid cartilage?
hyaline with perichondrium
what type of cartilage is the cricoid cartilage?
hyaline with perichondrium
what type of cartilage is the epiglottic cartilage?
elastic
which muscles in the larynx are involved in swallowing?
extrinsic skeletal muscles
which muscles in the larynx are involved in phonation- noise making?
intrinsic skeletal muscles
what is the trachea
a cartilaginous and membranous tube descending from the larynx. it branches into right and left primary bronchi and is only about 10 cm long
four layers of the trachea
mucosa
submucosa
cartilaginous layer
adventitia
characteristics of the mucosa in the trachea
mucous membrane of the trachea. consists of respiratory epithelium and lamina propria the lamina propria of loose connective dissue has many elastic fibers and contains MALT or BALT
characteristics of the submucosa in the trachea
thicker loose connective tissue layer that contains seromucous glands (mostly simple acinar)
characteristics of the cartilaginous layer in the trachea
16-20 C-shaped rings of the cartilage that open posteriorly. smooth muscle spans across the open region in the back of the rings. it is a discontinuous layer
characteristics of the adventita in the trachea
loose connective tissue layer that holds the trachea together. more dense loose connective tissue than in the submucosa or lamina propria
differences between right and left bronchus
right is shorter, more vertical and wider
the main bronchi divide into how many secondary (lobar) bronchi on each side?
three on the right, two on the left.
what is a bronchopulmonary segment
a region of the lung that the lobar bronchus will supply
what is the smallest portion of the lung that is easily resectable and has a definable blood supply and surround connective tissue layer
a bronchopulmonary segment
how many segmental bronchi on each side?
10 on the right, 8-10 on the left
how many branchings of bronchi are there
12
what size is a bronchiole?
about 1mm in diameter
primary or extrapulmonary bronchi have the same histological structure as what?
the trachea
what histological differences does the intrapulmonary bronchi have from the trachea
- hyaline cartilage is replaced with cartilage plates of irregular shape (at some point called chips instead of plates as they are so small)
- a layer of smooth muscle (muscularis mucosa) is present in the mucosa. this smooth muscle can change caliber in the bronchi and is more pronounced in smaller bronchials.
why is smooth muscle in secondary and smaller bronchi important
in allows for autonomic controlled bronchoconstriction and bronchodilation
what controls bronchodilation
sypathetics
what controls bronchoconstriction
parasympathetics
as branching occurs in the submucosa of the bronchi what happens to the seromucous glands?
they become less numerous
what cartilage is in the cartilaginous layer of bronchi?
discontinous layer of hyaline cartilage plates (with perichondrium) or chips
what is the histological differences between a bronchi and bronchioles?
- simple epithelium instead of pseudostratified (thinner and smaller)
- no cartilage
- no goblet cells
- no other ( seromucous) glands
- no submucosa
- prominent muscularis mucosa
which part of the bronchial tree has the most pronounced pronchoconstriction and dilation?
bronchioles
what are the two types of bronchioles?
terminal bronchioles
respiratory bronchioles
what is the largest part of the respiratory system
respiratory bronchioles
characteristics of terminal bronchioles mucosa
- ciliated simple columnar epithelium with interspersed club cells
- lamina propria- thin layer of loose connective tissue
- muscularis mucosa- quite prominent, although only a few layers of smooth muscle
what are club cells and what do they do
non-ciliated cells with a domed apex that projects into the lumen. they secrete surface active lipoprotein in the mucosa of bronchioles
what do terminal abd respiratory bronchioles not have
They do NOT have a submucosa, they do have an adventitia it is just VERY thin and blends with surrounding parenchyma
whats the difference between respiratory and terminal bronchioles?
respiratory bronchioles have alveoli with simple squamous epeithelium and gas exchange can occur here
whats in the mucosa of respiratory bronchioles
- numerous club cells with some ciliated cuboidal cells (the last ciliated cells in the respiratory tree)
- lamina propria- thin loose connective tissue
- muscularis mucosa- prominant thin layer of smooth muscle (thinner than in terminal bronchioles) only 1-2 smooth muscles cells thick
where are the last ciliated cells in the respiratory tree
in the respiratory bronchioles
what are alveolar ducts
elongated airways with minimal structure in the walls except containing alveoli and simple squamous epithelium, and a few elastic and reticular fibers
what do connective tissue fibers in the alveolar ducts do?
- allow expansion on inspiration
- provide passive contraction
- keep airways patent
is there smooth muscle in alveolus
yes and no! yes right at the entrance that act kind of like sphincters in ALVEOLAR DUCTS
no in alveolar sacs
what are alveolar sacs
blind-ended spaces surrounded by clusters of alveoli (the cul de sac with driveways being alveoli)
where are alveoli
respiratory bronchioles, alveolar ducts, and alveolar sacs
what is (inter) alveolar septum
the tissue between two alveoli, it consists of two layers of epithelium with a little bit of connective tissue and capillaries between them
what is the richest capillary bed in the body
alveoli!
what cells are found in the epithelium of the alveolar septum
- type 1 pneumocytes (type 1 alveolar cells)
2. type II pneumocytes (type II alveolar cells, great alveolar cells, septal cells)
what are type 1 pneumocytes
sqamous cells of the epithelium with thin cytoplasms that form the majority of the wall of the alveolus. they are joined to neighbors with zonula occludens. maximize control of gas exchange
what makes up the blood-air barrier?
- cytoplasm of endothelium (capillary)
- fused basement membranes of capillary and alveolar epithelium
- cytoplasm type 1 pneumocytes/ type 1 alveolar cells
what are the other names for type II pneumocytes
type II alveolar cells, great alveolar cells, septal cells
what are type II alveolar cells and what do they do
large cuboidal cells that bulge into the lumen of alveolus, appearing to have a foamy cytoplasm representing many vesicles of stored secretions. function
- secrete surfactant
- mitotic and need to replace type I and II pneumocytes
what is surfactant
a detergent mixture of lipid and protein that coats the luminal surface of alveolar walls which decreases surface tension on the walls of the alveolus and aiding in gas exchange
what is in the connective tissue of the alveolar septum
loose connective tissue, mostly reticular fibers but some elastic fibers. small amount of ground substance and a few fibroblasts
what type of capillaries are in the alveolar septum
continuous capillaries
what structural arrangement allows for maximal gas exchange in the alveoli
the basement membrane of type I pneumocytes are fused to the basement membrane of endothelium of the capillaries with NO connective tissue layer.
characteristics of an alveolar macrophage/ dust cells and what they do
cells found in the region of the lung parenchyma, relatively large cells with mottled cytoplasm from lyosomes and ingested material. exhibit ameboid movement (no consistent shape) found in CT of alveolar walls or in the lumen of the alveoli. they have no cilia
function: phagocytosis.
what lineage to dust cells come from
monocytes
what happens if the alveolar macrophage can not digest something
it is moved to the bronchioles to be swept out by ciia or stays in alveoli and sequesters. ex smokers
