structure and function of the respiratory system

componentss of URT

• nasal cavity

• oral cavity

• nasopharynx

• pharynx

• oropharynx

• epiglottis

• larynx

• trachea

• oesophagus

what is the diaphragm innervatd by

phrenic nerve- which is a somatic motor nerve

what are the external intercostal muscls innervated by

intercostal nerve

respiration in horses

• biphasic ventilation

• locomotion ventilation coupling

layers of the blood gas barrier

• surfactant

• type 1 alveolar epithelial cell

• basal laminar of epithelial cell

• connective tissue

• basal lamina of endothelial cell

• endothelial cell

• plasma

• rbc membrane

• 0.2-0.6 um thick

• large surface ae to volume

ficks law

rate of transfer of gas through a sheet of tissue is proportional to the tissue area and the difference in partial pressure between the two sides and inversely proportional to the tissue thickness

oxygen transport in the blood

• most carried by haemoglobin in red blood cells

• 3 percent dissolved in plasma

• reversible binding o2 to heme- high po2 is binding, low po2 is release

anatomy of urt

• where is oesophagus relative to the larynx

• where is the trachea relative to the oesophagus

• oesophagus lies dorsal to larynx

• trachea lies ventral to oesophagus

what is the blood gas barrier

• surfactant

• type 1 alveolar epithelial cell

• basal laminar of epithelial cell

• connective tissue

• basal lamina of endothelial cell

• endothelial cell

• plasma

• rbc membrane

• 0.2-0.6um thick

• large surface area to volume

diffusion of oxygen and carbon dioxide in the lung

• lower partial pressure in venous end compared to arterial end for oxygen

• vice versa for carbon dioxide

• move from an area of low to high partial pressure

diffusion of oxygen from capillary into tissue

• what is the systemic arterial blood pressure

• what is the pressure in the interstitial fluid

• what does this mean

• systemic arterial blood partial pressure 95mmHg

• Interstitial fluid 40mmHg

• large pressure difference meaning rapid diffusion

• partial pressure of blood leaving the capillaries drop

oxygen carriage in blood

• most carried by haemoglobin, some dissolved in plasma

• reversible binding oxygen to haem

• high po2 is binding, low po2 is release

carbon dioxide carriage in blood

• most as bicarbonate ion which is important for acid base balance

• some carried by Hb

• some dissolved in plasma

• reversible binding of carbon dioxide to amine radicals of Hb- carboaminohaemoglobin

importance of ventilation and perfusion

• to maintain proper concentrations of oxygen, carbon dioxide and hydrogen ion concentration in tissues

features of the upper respiratory system

• respiratory epithelium- nose to terminal bronchioles, lined by mucus which keeps epithelium moist and traps small particles

• cilia beats mucus towards the pharynx

• nasal cavity warms, humidifies and filters air, turbulent precipitation

features of the lower respiratory tract

• what are the 2 zones

• features of the 2 zones

CONDUCTING ZONE

• structural support (cartilage which decreases as descend to lower levels)

• modulation of airway diameter (smooth muscle)

• defence ( mucociliary escalator, mucus production by goblet cells and glands, ciliated epithelium

RESPIRATORY ZONE

• gas exchange (type 1 pneumocytes- very thin, and capillaries in intimate contact with air spaces)

• redistribution of ventilation (limited smooth muscle)

• maintain open alveoli (type 2 pneumocytes- produce surfactant)

pleural cavity

• is a potential space between the paritiel and visceral pleura

• contains small volume of serous fluid which helps lubrication

• surrounds lungs in the thoracic cavity

• is a vaccum

• negative pressure essential to pull lungs out when ribcage and diaphragm expand thoracic cavity

the pleura

visceral plura

• attached to surface of lung inc fissures

• elastic fibres

• continuous with parietal at the hilium

parietal pleura

• covers internal suface of thoracic cavity

• mediastinal- lines mediastinum

• costal- lateral wall of rib cage

• cervical- extension of pleural cavity into neck

• diaphragmic- lines cranial surface of diaphraghm

fish circulatory

• fish have a single circulatory system where there is a single atrium and a single ventricle.

• the sinus venonus recieves deoxygenated blood and acts as a reservoir and contains the pacemaker

• bulbus arteriosus is a thick walled chamber that extends between the single ventricle and the ventral aorta. allows maintenance of continuous blood flow into the gill arches. elastic

• conus arteriosus is the whole of the headward portion of the heart in fish which interveenes between the ventricle and anterior boundary of the pericardiac space. not all fish have- mostly replaaced by the non muscular bulbus arteriosus.

amphibian heart

• double

• 2 atria and a single ventricle

• spiral valve

mammals, birds and crocadilians

• fully developed septum between the atria (all) and ventricles (mammals and birds)

• cranial vena cava

• pulmonary veins- from lung

• aorta- to body

• pumonary artery- to lungs

• vena cava caudal

pulmonary vs systemic circulation

• pulmonary- to and from lung. right pumps deox to pulmonary circulation at low pressure

• systemic- to and from body. left side pumps oxygenated to systemic at high pressure

exterior anatomy

dog vs pig vs sheep

pressure

• cranial vena cava- deoxygenated blood at 3mmHg

• aorta to rest of body 100mmHg systemic

• pulmonary artery to lungs 12mmHg pulmonary

• pulmonary vein oxygenated blood 7mmHg

what surrounds the heart

pericardial sac

• epicardium- visceral pericardium

• parietal pericardium

layers of the heart wall

• endocardium

• myocardium

• epicardium

what connects the papillary muscles to the tricuspid and mitral valves

chordae tendinae

when the ventricles contract what is evasion of the cusps prevented by

action of the papillary muscles through the chordae tendinae

how many cusps do the semilunar valves hve each

3

cardiac skeleton

• helps provide structural integrity to the heart with fibrous tissue

• breaks up continuity between cardiac muscle cells of the atria and the ventricles

• four fibrous rings, right and left fibrous trigones, and finally the membranous aspects of the interatrial, interventricular and atrioventricular septa.

coronary arteries

• left and right branch from thebase of the aorta

• are the first branches off the aorta, 5 percent of cardiac output is delivered directly into the myocardium

• extensive capillarisation

function of elastic vessels

• large artries

• accomodate stroke volume- high elastance

• convert intermittent ejection into continuous flow

conduit ad feed vessels

• medium to small

• conduct blood flow to organs

resistance vessels

• arterioles, terminal arteries

• control arterial blood pressure

• control local blood flow

exchange vessels

• capillaries

• nutrient delivery to cells

• lymph formation

• removal of metabolic waste

• removal of metabolic waste

capacitance vessels

• venules, veins

• control cardiac filling pressure

• reservoir of blood

distribution of blood

artery structure

• transverse section- usually round with relatively thick wall

• rippled tunica intima and has internal elastic membrane

• thick, dominated by smooth muscle cells and elastic fibre in tunica media. has externall elastic membrane

• tunica externa- collagen and elastic fibres, nerve terminals, vasa vasorum

vein structure

• transerse section-usually flattened or collapsed with relatively thin wall

• tunica media- often smooth, no internal elastic membrane

• tunica media- thin, dominated by smooth muscle cells and collagen fibres, no external elastic membrane

• tunica externa- collagen and elastic fibres, smooth muscle cells, nerve terminals

arterioles and capillaries

what is flow

amount of blood flowing through a vessel at a given time

what is perufsion

flow per unit mass of tissue

calculating resistance to flow in a tube

what is the relationship between flow, pressure and resistance

• blood flow is directly proportional to the blood (hydrostatic) pressure gradient. if hydrostatic pressure gradient increases blood flow speeds

• blood flow (F) is inversely proportional to peripheral resistance (R)

• F= ΔP/R

• resistance is more important in influencing local blood flow because it is easily changed by alteirng vessel diameter

generation of interstitial fluid

• oncotic pressure- pressure exerted by the proteins

• hydrostatic pressure- pressure exerted by the blood

• movement of fluid depends on four variable known as starling forces

lymph formation

• blood enters the capillary around 35mmHg and leaves around 15mmHg

• filtration process provides continuous supply of intersitital fluid to form lymph

lymphatic system

• lymphatic vessles carry intersitital fluid to the cardiovascular system

• abnormal accumulation of interstitial fluid is known as oedema

• excess filtration

• defective resorption

• defective lymphatic drainage

• increased capillary permeability, increased capillary pressure, decreased plasma protein, decreased lymphatic drainage

mammalian foetus

• foramen ovale connecting the atria (becomes fossa ovalis)

• ductus arteriosus- vessels between the pulmonary trunk and aorta becomes the ligamentum arteriosum