Respiratory system Flashcards
The entrance to the respiratory system is through the …………….
external nares
The nasal chambers are divided into left and right by ………………………
a cartilaginous septum
The nasal turbinates are found within the nasal chambers. Describe the structure of the nasal turbinates.
Fine scrolls of bone
Covered by a ciliated mucous membrane with excellent blood supply
Which “anatomical direction” would you use to correctly describe the position of the nares on the head?
Rostral
What is a sinus?
Air-filled cavity within a bone
Describe the function of the paranasal sinuses.
Lighten the weight of the skull
Surfaces for heat exchange + mucus secretion.
The pharynx is the anatomical name for the throat area. It is divided into two areas. Name these two areas.
The naso-pharynx and the oro-pharynx
What is the function of the nasal turbinates?
Warm and moisten the air that is breathed in.
The ciliated mucous membrane helps to trap particles and waft them to the pharynx where they are swallowed (rather than enter the airways).
What structure separates the dorsal part of the pharynx from the ventral portion?
The soft palate
What structure separates the nasal cavity from the oral cavity?
The hard palate
What is the function of the Eustachian (auditory) tubes which connect the pharynx to the middle ear?
To equalise pressure on either side of the ear drum / tympanic membrane.
In terms of swallowing, what is the function of the soft palate?
The soft palate prevents food from entering the nasal passages during swallowing.
Describe the location of the larynx
The larynx is caudal to the pharynx, in midline and ventral in the neck
Describe three functions of the larynx
Air flow into respiratory tract
Stop anything but gases from entering the respiratory system
Vocalisation
Describe the structure and function of the epiglottis
The epiglottis is a flap of elastic cartilage.
Seals-off the entrance to the larynx when an animal swallows.
Describe the purpose of the incomplete rings of cartilage found in the walls of the trachea
Keep the trachea open (prevent it from collapsing).
The rings are incomplete on their dorsal surface which allows the oesophagus to ‘borrow space’ from the trachea during swallowing.
Describe the lining of the trachea
Ciliated mucous epithelium
- Mucus helps trap particles
- Cilia pushes the mucus up to the pharynx where it is swallowed
The tracheal lining is also sensitive and if stimulated, a cough reflex will aid in expelling foreign material.
How does the support of the bronchi differ from that of the support of the trachea?
Complete cartilaginous rings: no need to make way for expansion of the oesophagus.
Following the bronchial tree to the point where the cartilaginous support disappears, the bronchi become …………….
bronchioles
The smallest diameter branches of the bronchial tree are known as ……………….. which lead directly to the ………………
alveolar ducts
alveoli
Describe the structure of an alveolar sac.
Has a number of alveoli = thin-walled sacs surrounded by capillary networks.
What is meant by the term ‘pulmonary membrane’.
Epithelial lining of the alveolus.
Describe the process of gas exchange across the pulmonary membrane.
(Note that you can’t talk about gas exchange if you only mention one gas!)
Oxygen diffuses across the pulmonary membrane from the alveolar space to the capillaries in the pulmonary circulation
Carbon dioxide in the blood is excreted into the alveolus.
What is meant by the term ‘dead space’?
All parts of the respiratory tract which are not involved with gas exchange – i.e. everything except the alveoli.
They conduct air into and out of the alveoli.
Describe the location of the lungs.
The right and left lungs in thoracic cavity either side of the mediastinum.
They fill the thorax except for the mediastinal space in mid-line.
The lungs are lined on the external surface by a membrane called ……………
the pleura
Describe the purpose of the pleura.
Secrete pleural fluid: reduces friction as the lungs move during respiration.
The space between the lungs is known as the mediastinum. List four structures found within the mediastinum.
Heart
Blood Vessels
Oesophagus
Trachea.
The diaphragm is a sheet made from ………….. and it has a nerve supply from the ………………. nerve.
muscle
phrenic
The lungs fill the ……(a)……….. cavity except for the area in midline containing the heart and major vessels. The lungs are surrounded by the ………..(b)………… membranes. Caudally in the thoracic cavity is the ………….(c)………….; this separates the thoracic cavity from the …………(d)…………… cavity.
a. thoracic
b. pleural
c. diaphragm
d. abdominal
When the diaphragm contracts, it ………..(e)…………., which ……………(f)…………….. the amount of space in the thoracic cavity. The resulting ………..(g)…………… pressure causes …………..(h)…………………………..
e. flattens
f. increases
g. negative
h. air to move into the lungs
The external intercostal muscles cause the ribs to move …………….(i)………………….. which also ……………(j)……………… the space in the thoracic cavity and ……………..(k)………………… The internal intercostal muscles cause air to move ………….(l) …………….. the lungs during ……………(m)……………
i. upwards and outwards
j. increases
k. fills the lungs with air
l. out of
m. forced expiration
Breathing is controlled by the respiratory centres which fall within which areas of the brain?
The Pons and the Medulla
There are chemoreceptors within the body which measure chemicals within the blood to control respiration. Where are the main two groups of peripheral chemoreceptor and by what names are the known?
The aorta – the aortic glomi
The carotid arteries – the carotid glomi
Where are the main central chemoreceptors for respiratory control?
The medulla detects mainly CO2 levels
Which other substances are detected by the body’s respiratory chemoreceptors?
pH (acidity) and oxygen levels
What effect will an increase in CO2 levels have on the respiratory rate?
Respiratory rate will increase to remove the excess CO2
What effect will a decreased blood pH (a rise in acidity) have on the respiratory rate?
Respiratory rate will increase to remove the excess acidity (which is generally caused by high CO2 levels)
