Anatomy - Cardiovascular & Respiratory Histology Flashcards
what does the lungs normally look like on histology?
honeycomb like structure to increase surface for gas exchange
what is the conducting portion of the respiratory system?
nasal cavities to terminal bronchioles
what is the respiratory portion of the respiratory system?
respiratory bronchioles to alveoli
what is the conduction portion?
a series of interconnected cavities and tubes
help to filter, clean air and warm it
what allows the gas exchange?
vast network of capillaries
what are the nasal cavities down to the bronchi lined with?
respiratory epithelium
what is the respiratory epithelium?
ciliated pseudo stratified (loots like lots of layers but they all actually touch the BM) columnar epithelium with goblet cells
what is the function of goblet cells?
secrete mucus that lines the surface and is sticky that traps any inhaled dust or debris
what Is the function of the cilia in the respiratory tract?
moves the trapped particles caught in the mucus up towards the pharynx out of the respiratory system
wha typically happens to someone who smokes?
they have reduced cilia
what supports the trachea?
10-12 C shaped hyaline cartilages
help to maintain an open airway
where are the chondrocytes located?
cartilage cells embedded in the C shaped cartilage that surrounds the trachea
what joins the 2 ends of the C shaped cartilage in the trachea?
smooth muscle (trachealis muscle)
why is the trachealis muscle important?
allows for change in diameter of the trachea
important for coughing
can change shape rapidly
what kind of epithelium is the trachea lined with?
stratifciliated pseudo stratified columnar
what is in the submucosa of the trachea?
seromucous glands
adds to the sticky layer to catch any dust or debris
which layers together form the mucosa?
the epithelium and the lamina propria
what are seromucous glands?
produce watery and mucus secretions which are delivered to the luminal surface by ducts
what is the structure of the brocnhi?
-irregular plates of cartilage that help to hold the airways open
-these decrease in frequency and size as we move down the trachea
what happens as we move down the bronchi?
less need for mucous secretion and therefor less submucosal glands and goblet cells
what is the structure of the bronchioles?
lose the cartilage
no submucosal glands
smooth muscle makes up most of the wall and keeps the bronchi open
narrower and smaller airways which can be blocked easily so we don’t want much mucous
what type of epithelium are larger bronchioles lined with?
simple ciliated columnar epithelium (not pseudostratified) which has few goblet cells
what happens to the epithelium as the bronchioles decrease in size?
epithelium becomes simple cuboidal with few ciliated cells and increasing number of club cells (Clara cells)
what are club cells (Clara cells)
small cuboidal shaped cells which are found in the bronchioles which have a protective function and secrete antimicrobial and anti-inflammatory immune regulating proteins and participate in the biotransformation of many of the harmful and toxic compounds introduced to the lungs with inhaled air
what is the last part of the conducting system?
terminal bronchioles
they lead into the respiratory bronchioles
what are respiratory bronchioles?
where gas exchange is beginning to take place
what do respiratory bronchioles lead to?
alveolar ducts
what do alveolar ducts lead into?
alveolar sacs
what are alveolar sacs?
open into 2-3 alveoli and provide a large surface area for gas exchange
what cells make up the walls of alveoli?
type 1 pneumocytes
type 2 pneumocytes
what are type 1 pneumocytes?
flattened (squamous) with flat, dark oval nuclei and very thin cytoplasm
they are primarily involved in gas exchange
40% of the number of cells in alveoli
provide a thin layer between the air and the capillaries
what is the surface area composition of alveoli?
type 1 pneumocytes - 95%
type II pneumocytes - 5%
what is a type II pneumocyte?
cuboidal cells that bulge into the alveolar space and produce surfactant
progenitor cells and can proliferate to replace both type I and type II pneumocytes after lung injury
account for 60% of cells in the alveoli
what is surfactant?
produced by type II pneumocytes
acts like detergent and reduces the surface tension of the alveoli and prevents them from collapsing on expiration
what makes up the blood-air barrier?
type I pneumocytes
endothelial cells of the capillaries
the fused BM of these cells in the middle
what are the 3 layers of cardiovascular histology?
inner layer
middle layer
outer layer
what makes up the inner layer of cardiovascular histology?
endothelium + sub endothelial connective tissue
what makes up the middle layer of cardiovascular histology?
contains muscle tissue
what makes up the outer layer of cardiovascular histology?
adventicia (vessels) or serosa (heart)
what is the structure of the epicardium?
epithelial layer called the mesothelium and a thick connective tissue layer containing lots of adipose tissue that surrounds the coronary vessels
simple squamous epithelium
serous fluid is produced here
visceral layer of the serous pericardium
what is the structure of the myocardium?
cardiac muscle with connective tissue capillaries in there
thickest layer
formed from cardiac muscle cells
striated cells and branching
central nucelus
intercalated discs found inbetween each cardiomyocytes with GAP junctions inbetween
blood vessels providing blood supply to cardiac muscle
what is the structure of the endocardium?
thin layer
epithelium called the endothelium and a thin connective tissue layer
simple squamous epithelium
thin single cell layer of flattened cells
underlying connective tissue
provides a smooth lining of the heart
gives a smooth non adherent layer to facilitate bloodflow
have blood vessels and purkinje fibres
what is the function of GAP junctions between cardiomyocytes?
which help synchronise contractions of the cardiac muscle cells
where are the purkinje fibres located?
endocardium
what is the structure of purkinje fibres
part of the conduction system of the heart
specialised cardiomyocytes
larger than cardiomyocytes
look paler as they have fewer myofibrils but have lots of mitochondria and glycogen
very good at conducting signlas
lots of GAP junctions
what is the structure of the tunica intima?
endothelium lining
simple squamous epithelium with some connective tissue
what is the structure of the tunica media?
thicker
smooth muscle
what is the structure of the tunica adventitia?
outer connective tissue layer
vary in thickness depending on size of the
if the tunica adventitia has its own blood supply what would this be called?
vasovasorum
what characterises elastic arteries?
receive high pressure blood from heart during systole
lots of bundles of elastic fibres or elastic bundles in the tunica media
allow the walls of the arteries to resist pressure and expand
the walls can recoil and maintain arterial BP
what characterises muscular arteries?
distributing blood to smaller arteries in the organs
thick tunica media dominated by smooth muscle cells
allows for vasoconstriction and vasodilation
they have elastic lamina but not lots of elastic fibres
what is internal elastic lamina?
forms a clear boundary between the tunica intima and tunica media
what is the external elastic lamina?
forms a boundary between tunica media and tunica adventitia
Which layer is the visceral pericardium?
Epicardium
What is deep to the mesothelium?
Layer of connective tissue which can vary in thickness and contains abundant adipose tissue along with coronary vessels and nerves
What is the type of epithelium in the upper airways?
pseudostratified ciliated columnar epithelium
What is the lowest vertebral level reached by the pleura?
T12
Which type of epithelium forms the alveoli?
simple squamous
