CBT1 Anatomy of respiratory and cardiovascular systems Flashcards
What is the main job of the respiratory system?
Most efficient delivery of air into the lungs
What is the main job of the cardiovascular system?
most efficient delivery of oxygen and all the other blood-borne molecules (proteins, lipids, carbohydrates) to the tissues
Name the layers of the chest wall and lungs from superficial to deep
Skeletal muscle - affixed Skeleton - affixed Parietal pleura - separated by pleural fluid Visceral pleura - affixed Lung
What are the two parts of the lung organ?
The lung tissue and the chest wall
Describe the structure of the chest wall?
rigid support structure comprising mostly the ribcage, sternum and intercostal muscles. It naturally recoils outward.
Describe the structure of the lungs
soft tissue structures, very elastic, and naturally recoil inward. They provide a large surface area for gas exchange.
What are the two layers of connective tissue in between the lungs and chest wall?
- (visceral and parietal) pleura
- pleura fluid (lubricating fluid)
What is the pleura membrane attached to the lungs called?
visceral pleura
Where is the parietal pleura attached?
Inner surface of chest wall
What do the pleura act as?
The lung-chest interface and are integral to normal chest function
What volume of pleural fluid is there in between the pleura?
A few millilitres
What should the interpleural cavity pressure always be in healthy individuals?
negative (-5 cmH20)
atmospheric pressure = 0 cmH20
SA of lungs is roughly equal to?
Tennis court, much of this SA is in the alveolar region
How many litres of air do we inhale on average per day?
12,000 litres
What does patent refer to?
open airways
How are the cartilaginous airways held open?
- C-shape cartilage strips
- The open side of the dorsal strip is the dorsal side
Where is the open side of the cartilaginous airway most important and why?
Trachea, where the open side accommodate the oesophagus, and does not impede swallowing
Describe how the tensile strength of the cartilaginous airways is formed
The C-rings are slightly offset with each other (not stacked) thereby increasing airway wall support properties
How do the bronchioles remain open?
Not by cartilage but by surfactant to reduce surface tension and limit airway collapse
What are acini?
Discrete anatomical alveolar regions
What does bifurcate mean?
Branching off into two new branches called dichotomous branching
What do the two main bronchi split into?
four smaller extrapulmonary bronvhi
As the number of airways progressively increases, what happens to their diameter and length? and the cross-sectional area?
proportionally decreases
cross-sectional area increases markedly
In chronic obstructive pulmonary disease and other respiratory diseases which increase difficulty breathing, what is the diameter of the bronchioles?
<2mm
Describe the relationship between resistance to airflow and airway generation
There is an initial relatively small increase in resistance in the first few airway generations. But then resistance falls markedly, with virtually no resistance in the respiratory zone
How many different cell types are found in the airway? why would this change?
22
acute or chronic disease status
Describe the structures of the airway wall superficial to deep
Submucosa:
Cartilage
smooth muscle (tracheal/bronchial)
(submucosa gland found within smooth muscle)
(blood vessels found within smooth muscles too)
Mucosa:
Goblet and ciliated cells beside each other
mucus
airway
Describe how the airways are cleared of inhaled particles
Mucus on the epithelia surface traps inhaled particles. beating cilia moves the mucus. This process is called mucociliary clearance
What is the alveolar region also known as?
lung parenchyma
Within the alveolar region, what has close interactions?
type 1 alveolar cell
capillary endothelial cell
erythrocyte
fibroblasts
What do type 2 alveolar cells do?
They have a variety of functions
Replicate to replace type 1 cells
Secrete surfactant and antiproteases
Contribute to xenobiotic metabolism
What do macrophages in alveolus do? How many normally in healthy individuals?
2-3/alvelolus
ingest inhaled particles and microbes
What do fibroblasts do to aid the alveoli?
produce extracellular matrix that helps to hold the alveolar unit structures together
What % of the alveolar surface do type 1 epithelial cells (EP1) cover?
95%
What cells does gas exchange occur between?
EP1 cells
Dichotomous branching of the airways facilitates….?
the marked reduction in resistance to airflow as air moves towards the alveolar region
Why are EP1 cells able to carry out gas exchange?
They are extremely thin
Very briefly describe the human cardiovascular system
organ system that conveys blood through vessels to and from all parts of the body, carrying nutrients and oxygen to tissues and removing carbon dioxide and other wastes. It is a closed tubular system in which the blood is propelled by a muscular heart.
What are the two circuits of the cardio system?
Pulmonary and systemic
What are the pulmonary and systemic compartments made up of?
Arterial
Capillary
Venous
What is the primary function of the heart
Muscular pump propelling blood around the body
Describe arteries
- Receive blood at high pressure and velocity and conduct it through the body
- Thick elastic walls made up of elastic fibrous tissue and muscle cells
- Narrow lumen
What are arterioles?
What the arteries branch into they are short narrow muscular vessels
How many generations of airways are there in humans?
23
What do arterioles branch into?
capillaries
What do capillaries feed into?
venules
What are venules?
small vessels that converge into veins that take blood back to the heart
What is the heart enclosed in?
Pericardial sac
What is the pericardial sac lined with?
The parietal layers of a serous membrane
What do the visceral layer of the serous membrane form?
epicardium
What does blood from the atrium go into?
the Aorta
Where does blood from the right ventricle go into?
The pulmonary arteries
Describe the 4 layers of the heart wall from superficial to deep
(Pick Eight More Elephants)
Pericardium (double walled membranous sac)
Epicardium (inner layer)
Myocardium (muscular layer)
Endocardium
Name the four internal chambers of the heart
- right atrium
- right ventricle
- left atrium
- left ventricle
What are the two types of values that keep the blood flowing in one direction?
atrioventricular values
semilunar values
Where are the two types of values found
atrioventricular values found between atria and ventricles
semilunar values found at the bases of the large vessels leaving the ventricles
Briefly describe how pumping works in the heart
Both the atria and the ventricles contract at the same time, thus acting as two pumps, one on the right and one on the left simultaneously
What does the pulmonary circulation transport?
Oxygen poor blood from the capillaries to the right ventricle to the lungs where blood picks up oxygen
What does the systemic circuit transport?
Oxygen and nutrient rich blood to all body tissues and removes carbon dioxide and waste products. It carries oxygenated blood from the left ventricle, through the arteries to the capillaries in the tissues of the body
What are the only vessels that branch from the ascending aorta?
Coronary arteries
What is blood supply for the brain provided by?
Internal carotid
Vertebral arteries
What do venules converge into?
Veins
Where does blood from the veins go?
Superior vena cava or inferior vena cava
What supplies blood to the myocardium?
right and left coronary arteries
After blood passes through the capillaries in the myocardium, where does it go?
It enters a system of cardiac (coronary) veins. These then drain into the coronary sinus, which opens into the right atrium
What are the right atrium and ventricle separated by?
Tricuspid valve
What are the left atrium and ventricle separated by?
Mitral valve
What do the semilunar valves do?
Keep the blood flowing in one direction
What is the main reason foetal circulation is different from adult circulation
several organs are not functioning before birth. The foetus obtains nutrients and oxygen from the mother and its wastes are carried away by the maternal circulation.
How many arteries and veins does the umbilical cord have?
Two arteries - carry foetal blood to the placenta
One vein - carries oxygen and nutrient-rich blood from the placenta to the foetus
The foetal liver is by passed by what?
ductus venosus
The foetal lungs are by passed by what?
ductus arteriosus foramen ovale (small hole in heart septum, between atria of the heart)
What % of total blood volume is in the systemic arterial system at any given time?
10%
How do substances pass through capillaries?
Diffusion
Filtration
Osmosis
What is fluid movement across the capillary determined by?
Combination of hydrostatic and osmotic pressure
Do veins have more or less smooth muscle and connective tissue than arteries?
less
What do venous valves do?
Help ensure blood in the veins flows towards the heart, especially important in the rams and legs to prevent backflow of blood due to the pull of gravity
Explain why foramen ovale is needed?
Before a baby id born they do not use their lungs to get oxygen rich blood
What is the ductus arteriosus for?
It is a blood vessel connecting the main a blood vessel connecting the main pulmonary artery to the proximal descending aorta. It allows most of the blood from the right ventricle to bypass the foetus’s non-functioning lungs. (It does so because the blood is partially oxygenated from mother)
In a feotus’ right atrium and ventricle, what type of blood is there?
Partially oxygenated (contains both deoxygenated from feotus’ body and oxygenated from mothers body.
What type of blood goes from the right atrium to the left atrium via the foreman ovale in a foetus?
Partially oxygenated (by passing pulmonary circulation and entering general circulation) - some mixing has occurred but it is still oxygenated enough
What is the role of the ductus venous?
It contains oxygen rich blood from mother and brings to foetus right atrium before going through the liver as it is very nutrient rich and the liver processes these nutrients. Like the hepatic vein in function (latter part)
how does umbilical vein and umbilical artery act?
To get blood to and from placenta, where the foetus and mother’s blood vessels interface
