Last minute (Year 1) Flashcards
What structures form first from the trachea, behind the oesophagus, during development?
Lung buds
What embyrological structure forms the tongue?
Tuberculum impar
What is meant by oesophageal atresia?
This is the formation of a blind ending oesophagus, in which there is no connection between the distal and proximal oesophagus
What can arise from oesophageal atresia?
The baby can’t swallow amniotic fluid, which it usually does to maintain homeostasis
This causes a build up of amniotic fluid around the baby known as polyhydramnios
What is polyhydramnios?
This is a build up of amniotic fluid around a baby
What trilaminar layer forms the lining of the respiratory tract?
Endoderm
What trilaminar layer forms the cartilage and smooth muscle surrounding the bronchial tree?
Visceral mesoderm
What stage of respiratory development occurs between 26 days and 6 weeks?
Embryonic
What stage of respiratory development occurs between 6 and 16 weeks?
Pseudoglandular
What stage of respiratory development occurs between 16 and 28 weeks?
Canalicular
What stage of respiratory development occurs between 28 and 36 weeks?
Saccular
What stage of respiratory development occurs between 36 weeks and early childhood?
Alveolar
What occurs in the embryonic period of respiratory development?
Respiratory diverticulum forms
Initial branching to give lungs, lobes and segments
What occurs in the pseudoglandular stage of respiratory development?
14 more generations of branching, forming the terminal bronchioles
What occurs in the Canalicular stage of respiratory development?
Terminal bronchioles branch into respiratory bronchioles and alveolar ducts
What occurs in the Saccular stage of respiratory development?
Terminal sacs form
Capillaries establish close contact
What occurs in the alveolar stage of respiratory development?
Alveoli mature
What type of cell forms the blood-air barrier?
Type I pneumocystis
What are the functions of the nasal cavity?
Warming
Moistening
Filtering
Olfaction
Where in the nasal cavity are the olfactory receptors?
Roof
What type of cell lines the vestibule (Opening) of the nasal cavity?
Keratinised stratified squamous epithelium
What is respiratory epithelium?
Pseudostartified ciliated columnar epithelium with goblet cells
What type of epithelium lines the nasal cavity?
Respiratory epithelium
What epithelium lines the oropharynx?
Non-keratinised, stratified squamous epithelium
What epithelium lines the anterior and upper epiglottis?
Non-keratinised, stratified squamous epithelium
What epithelium lines the distal epiglottis?
Respiratory epithelium
What type of cartilage forms the epiglottis?
Elastic cartilage
What epithelium lines the vocal folds?
Stratified, squamous epithelium
Where do most foreign objects travel in the bronchial tree?
Right main bronchus
What joins the 2 ends of the C shaped tracheal cartilage?
Tracheal muscle
Describe the changes as the move towards the terminal bronchioles
Hyaline cartilage lost
Goblet cells lost
Columnar -> Cuboidal
What are terminal bronchioles?
These are the smallest bronchioles that lack respiratory capability
What are respiratory bronchioles?
These form from the terminal bronchioles
They can perform respiration
They form alveoli
What are clara/club cells?
Non-cilated cells that project above the level of adjacent ciliated cells found in terminal bronchioles
What is the function of clara/club cells?
Stem cells
Detoxification
Immune modulation
Surfactant production
What are the 2 types of alveolar cells?
Type I pneumocytes
Type II pneumocytes
What is the function of type I pneumocytes?
Form the blood air barrier
Simple squamous epithelial cells
What are type II pneumocytes?
Polygonal shaped cells with mirovili
Contain membrane bound lamellar bodies which contain surfactant, which can be released via exocytosis
What are alveolar macrophages?
Aka dust cells or heart failure cells, which are found in the septa or migrate over luminal surfaces and phagocytose inhaled particles, before moving up the bronchial tree and getting swallowed, or moving into the septal connective tissue
Describe the histology of the visceral pleura
Simple squamous epithelium (Mesothelium)
Backed by layers of fibrous and elastic connective tissue
What is an ecological study?
Analysis of grouped data from summaries of individual data
Disease rates and exposures measured in a population and their relation is examined
Strengths of ecological study?
Rapid
Inexpensives
Limitations of ecological study
No individual data
Unsure is those with disease had exposure (Ecological fallacy)
What is a cross sectional study?
Measurement of exposure and outcome simultaneously
Asses prevalence and distribution of a disease in a population
Strengths of cross sectional study?
Provides prevalence
Better for chronic illnesses
Limitatuons of cross sectional study?
Can’t estimate incidence
Prone to bias (Those with disease more likely to remember exposure)
What is incidence?
rate of disease
What is prevalence?
Number with disease at any one time
What is a case control study?
Comparing 2 groups of people, with and without disease, and with and without exposure
What are some strengths of case control study?
Quick
Small sample size
Evaluate multiple exposures
Limitations of case control study?
Cannot determine incidence or prevalence
Cannot determine causality
Not useful for rare exposure
What is a cohort study?
Group of people with or without exposure are followed up over a long period of time to see if they develop the disease
What are the strengths of a cohort study?
Determines incidence
Detemines causality of exposure
What are the limitations of cohort study?
Expensive
Time consuming
Can lose people in the trial
What is pre-load?
Initial stretching of heart wall due to blood
What is after-load?
The force with which the heart must pump to move blood out
What is the Frank-Starling mechanism?
Increased end diastolic volume => Increased stroke volume as the heart will pump harder
Give the calculation for resistance to flow
What performs extrinsic control of blood vessels?
Nerves and hormones
What type of innervation innervates the vascular smooth muscle?
Sympathetic
What adrenoceptor is found in vascular smooth muscle?
Alpha 1
What is the vasomotor tone of blood vessels?
This is a the tonic, low level sympathetic discharge of sympathetic nerves, due to noradrenaline, causing constant, partial constriction
How does increased sympathetic tone affect blood vessels?
Vasoconstriction
How does decreased sympathetic tone affect blood vessels?
vasodilation
Where is adrenaline released in the body
Adrenal medulla of the adrenal glands
What are the affects of adrenaline on the body?
Vasoconstriction (Alpha 1)
Bronchodilation (Beta 2)
What are intrinsic mechanisms of blood vessels?
These are local changes in blood flow to match the needs of tissue
Which is more dominant, extrinsic or intrinsic mechanisms?
Intrinsic mechanisms can override extrinsic mechanisms
What types of stimuli can affect instrinsic mechanisms?
Chemical metabolites
Physical stimuli
What are some types of chemical metabolites that affect intrinsic mechanisms?
Local metabolites
Local humeral agents
Organic nitrates
What are some factors that cause releases eof local metabolites and thus cause vasodilation?
Decreased local pO2
Increased local pCO2
Decreased local pH
Increased extra-cellular K+
Adenosine release from ATP
What are some local humoral agents that cause vasodilation?
Histamine
Bradykinin
Nitric oxide
What are some local humeral agents that cause vasoconstriction?
Serotonin
Thromboxane A2
Leukotrienes
Endothelin
How is nitric oxide released?
Stress of vascular endothelium causes the release of calcium in the cells, which activates nitric oxide synthase
Nitric oxide synthase converts L-arginine into nitric oxide in the vascular endothelium
What are some physical stimuli that can affect blood vessels?
Temperature
Myogenic response to stretch
Sheer stress
How does cold affect blood vessels?
vasoconstriction
How does warm affect blood vessels?
Vasodilation
What is the myogenic response to stretch?
The brain is tightly enclosed in the skull
This means blood vessels can’t expand
So if MAP rises, the blood vessels constrict to prevent increased intracranial pressure
If MAP falls, the blood vessels dilate to prevent decreased intracranial pressure
How does sheer stress affect blood vessels?
Dilatation f arterioles causes sheer stress in arteries upstream, making them dilate
What sensory nerves are involved in sneezing?
V1 and V2
Where are cough receptors located?
Oropharyngeal mucosa
Laryngopharyngeal muscosa
Laryngeal mucosa
What are carotid sheaths?
These are tubes of deep fascia that contain the common carotid arteries, the internal jugular vein and the vagus nerve
They attach to the bones of the posterior skull
What nerve sense a stimulus to cause a cough in the nasal and oral pharynx?
IX - Glossopharyngeal
What nerve senses a stimulus to cause a cough in the laryngopharynx and larynx?
X - Vagus
What nerves form the pulmonary plexus of nerves?
Post-synapetic parasympathetic
Vagus nerve branches
Visceral afferents
What nerves sense a stimulus to cause a cough in the lungs?
Visceral afferent nerves that travel to the medulla
What nerve closes the rima glottidis in a cough?
Vagus - X
What muscles cause closure of the rima glottidis?
Intrinsic muscles of the larynx
IN what direction do the external oblique muscles travel?
Hands in pockets
In what direction do internal oblique muscles travel?
Hands on pecs
IN what direction do transversus abdominus muscles travel?
Horizontal
What nerves supply motor innervation during a cough?
X and IX