Vet Term Flashcards
what is the function of the respiratory system?
the exchange of oxygen and carbon dioxide between the environment and the tissues
what does the respiratory system include and what two zones can the structures be divided into?
the lungs and a series of airways that connect the lungs to the external environment conduction zone (brings air into and our of the lungs) respiratory zone (lines with alveoli where gas exchange occurs
what are the 7 structures of the conducting zone?
nose nasopharynx larynx trachea bronchi bronchioles terminal bronchioles
what are the 2 roles of the conducting zone?
bring air into and out of the respiratory zone for gas exchange
humidify, warm and filter the air before it reaches the critical gas exchange region
what is the conducting zone also known as and why?
anatomic dead space
gas exchange does not occur in these pathways
what is the conducting airways lined with and what is its function?
lined with mucus-secreting and ciliated cells function to remove inhaled particles
How are large and small particles removed from the airway?
large= filtered out in the nose small= captured my mucus and swept upward by the rhythmic beating of the cilia
what does the wall of the conducting cone contain, what two categories are they divided into and what is the cause of them?
contain smooth muscle
sympathetic system/circulating epinephrine= dilation of the airways
parasympathetic system= constriction of the airways
what does changes in the diameter of conduction airways result in?
changes in their resistance, which produce changes in airflow
what are the 3 structures included in the respiratory zone and what is the zone’s function?
respiratory bronchioles, alveolar ducts, alveolar sacs
gas exchange
what kind of structure are respiratory bronchioles and what are they made up of?
transitional structures
have cilia and smooth muscle
alveoli occasionally bud off their walls
what are alveolar ducts lined with, what two things don’t they contain and what do they terminate in?
lined with alveoli
contain no cilia and little smooth muscle
terminate in alveolar sacs, lined with alveoli
what are alveoli?
poush like envaginations of the walls of the respiratory bronchioles, the alveolar ducts and the alveolar sacs
what are 2 characteristics of alveoli, what are they considered and why?
walls are thing and have a large surface for diffusion of gases
poorly perfused with blood= dead space
what are alveolar walls rimmed and lined with?
rimmed with elastic fibers
lined with epithelial cells (alveolar cells)
what is another name for alveolar cells, what are the two types and what are their function?
pneumocytes
Type 1= primary source for angiotensin-converting enzyme (ACE)
type 2= synthesize pulmonary surfactant
what are two functions of pulmonary surfactant synthesized by type 2 pneumocytes?
reduction of surface tension of alveoli
regenerative capacity for type 1 and 2 pneumocytes
what do alveolar cells contain, what is their function and how do they perform their function?
contain alveolar macrophages
keep alveoli free of dust and debris
macrophages fill with debris and migrate to bronchioles, where the beating cilia carry the debris to the upper airways and the pharynx to be swallowed or expectorated
what are the two phases of the respiratory cycle?
inspiratory
expiratory
what does inspiration involve?
an enlargement of the thorax and lungs when an accompanying inflow of air
The thorax enlarges by the contraction of what (2) and in which direction?
diaphragm: caudal direction
external intercostal muscles: cranial and outward direction
under normal breathing conditions, does inspiration or expiration require greater effort, and what is an exception?
inspiration (active)
expiration= passive
except in horses
when is expiration an active process? (2)
times of accelerated breathing
when there are impediments to the outflow of air
what contracts to assist in expiration? (2)
internal intercostal muscles
abdominal muscles
what are the two types of breathing?
abdominal
costal
what is abdominal breathing characterized by and in what conditions is it more frequently used?
visable movements of the abdomen- protrudes during inspiration and recoils during expiration
normal conditions
what is costal breathing characterized by and in what conditions is it more frequently used?
pronounced rib movements
during painful conditions of the abdomen
define eupnea
normal quiet breathing
define dyspnea
difficult breathing
define hyperpnea
increased depth, frequency of both
define polypnea
rapid shallow breathing (similar to panting)- increased frequency but not depth
define apnea
cessation of breathing (can be a transient state)
define tachypnea
excessive rapidity of breathing
define bradypnea
abnormal slowness of breathing
define normoventilation
normal ventilation in which a PaCO2 of 40 mmHg is maintained
define hyperventilation
alveolar ventilation increased beyond the metabolic needs and PaCO2 below 40 mmHg
causes respiraroty alkalosis
define hypoventilation
alveolar ventilation decreased below metabolic needs and PaCO2 above 40 mmHG
acute causes respiratory acidosis
what is pulmonary ventilation?
the process of exchanging of gas in the airways and alveoli with gas from the environment
what is the main function of ventilation and what does metabolic oxygen needs require and animal to do?
replenish O2 and remove CO2
take a certain volume of air into the lungs, especially alveoli, each minute
what surrounds the lung in the thoracic cavity?
a thin layer of pleural fluid
what kind of pressure (+/-) is between the lung and the thoracic cavity and why?
negative pressure
continual suction of excess fluids into lymphatic channels
what is another name for atmospheric pressure?
barometric pressure
how are respiratory pressures expressed?
relative to atmospheric pressure (- or +)
what is atm pressure when relative pressures are used?
zero
what must pressure in the lungs be in order for air to flow?
the pressure must be higher or lower than the barometric pressure
what is pleural pressure and that is another name for it?
intra-pleural pressure
the pressure exerted outside the lungs within the thoracic cavity
what is pleural pressure compared to atm pressure and when does the negative pressure increase?
less than atm pressure (slightly negative)
negative pressure increases during inspiration with the increase in volume
what is alveolar pressure and what is another name for it?
intra-pulmonary pressure
the pressure within the alveoli that increases and decreases with each breath
what is alveolar pressure compared to atm pressure?
equal to atm pressure at the end of the inspiration and expiration (rest period)
what must the pressure int he alveoli do in order to cause inward flow of air?
the pressure must fall to slightly negative during inspiration
what it transpulmonary pressure?
the pressure difference between the alceolar pressure and pleural pressure in the lungs
what is recoil pressure?
a measure of the elastic forces in the lungs that tend to collapse the lungs at wach instant of respiration
what is the volume of the transpulmonary pressure in relation to the elastic recoil pressure of the lung?
equal and opposite of one another
what happens if transpulmonary pressure is zero, and what is that called?
alveolar pressure= pleural pressure, the lung collapses as a result of their inherent elastic recoil
pneumothroax
what is normal transpulmonary pressure?
positive pressure
what is recoil pressure due to? (2)
stretching of elastin and collagen fibers by lung inflation
surface tension of fluid lining the alveoli
What effect does tension in the wall of the alveolus do versus pressure inside the alveolus to the lung?
tension= contract it pressure= expand it
what are surfactants?
surface-active substances for which molecules have less attraction
what are surfactants made of, what produces them, and where are they found?
lipoprotein complex= 30% protein and 70% lipids
produced by type 2 pneumocytes
accumulate at the surface of the alveoli
what are 2 roles of surfactants?
decrease the surface tension
displace water molecules
what are two results of the action of surfactants?
prevent collapse of the lungs at the end of expiration
increases pulmonary compliance (reduce the work of inflating the lungs)
what must the lung be able to do in order for inspiration to occur, what is this called?
the lungs must be able to expand when stretched
must have compliance
what is another term for lung compliance and what is it the extent of?
distensibility
the extent to which the lungs will expand for each unit increase in transpulmonary pressure
what factors affect complaince?
conditions that destroy lung tissue or cause it to be fibrotic or edematous or that impede lung expansion
how does a lack of surfactant affect compliance?
decreased compliance
what must the lung be able to do in order for expiration to occur, what is this called?
the lungs must get small when the stretching force is released
elasticity
what is elasticity?
tendency to return to its initial size after being distended
why are lungs elastic?
high content of elastic fibers (collagen/ elastin)
when is elastin increased/reduced?
increased during inspiration when lungs are stretched
reduced by elastic coil during expiration
what foes elasticity help with during expiration and with what other structures?
aids in pushing air out
with thoracic structures
what is helpful with understanding mechanics of pulmonary ventilation?
boyle’s law
what does boyle’s law relate and what does the law state?
relates pressure and volume
the pressure exerted by a constant number of gas molecules in a container is inversely proportional to the volume of the container
how does increasing/decreasing volume affect pressure?
inc volume= dec pressure
dec volume= inc pressure
what are 5 components of the urinary system?
kidneys ureters urinary bladder urethra genital organs
what is the main role of the urinary system?
removing waste products from blood and eliminating them as urine
where are the kidneys located and what is it surrounded by?
retroperitoneal space
in the posterior wall of the abdomen, outside the peritoneal cavity
surrounded by a tough, fibrous capsule
what 5 structures of the hilum?
renal artery renal vein lymphatics nerve supply ureter
what carries the final urine from the kidney to the bladder?
ureter
what are the two major regions of the kidney?
outer cortex
inner medulla
what is the medula divided into?
cone-shaped masses of tissue= renal pyramids
where does the renal pyramid originate and where does it terminate?
ordinates at the border between the cortex and medulla
terminates in the papilla
where does the papilla project into?
the space of the renal pelvis
what is the renal pelvis
a funnel-shaped continuation of the upper end of the ureter
what is the outer border of the renal pelvis is divided into, what does it extend into and what is its role?
open-ended pouches= major calyces
extend downward and divides into minor calyces (collect urine from tubules of papilla)
what structure of the calyces, pelvis and ureter helps propel the urine toward the bladder?
contractile elements
what are 6 other functions of the kidneys?
regulation: water& electrolyte balance, arterial pressure, acid-base balance, erythrocyte production
secretion, metabolism & excretion of hormones
gluconeogenesis
how does the kidneys regulate water and electrolyte balance?
alter NA excretion in response to changed in ECF or plasma concentrations
also for Cl, K, Ca, H, Mg, PO4
what are two ways the kidneys regulate arterial pressure?
long-term: excrete variable amounts of Na & H20
short-term: secrete hormones (renin) that lead to the formation of vasoactive substances (angiotensin 2)
what two ways does the kidneys regulate acid-base balance, what are 2 types of acids and where are they generated?
Excrete acids & regulate the body fluid buffer stores
sulfuric acid & phosphoric acid
generated by the metabolism of proteins
how do the kidneys regulate erythrocyte production?
secrete erythropoietin, which stimulates the production of RBC by hematopoietic stem cells in the bone marrow
what does severe kidney disease lead to?
anemia
how do the kidneys regulate Vit D production?
produce active form of Vit D (calcitriol)
what are two roles of calcitrol?
Ca reabsorption by the GI tract
Ca/PO4 regulation
how do the kidneys promote gluconeogenesis?
synthesize glucose from AA and other precursors during prolonged fasting
what is the functional unit of the kidney, what is its role and what is an important fact about them?
nephron
form urine
don’t regenerate
what are two components of a nephron?
glomerulus
tubule
what is glomerulus made of, what is its function, what is it covered by and what is it encased in?
group of glomerular capillaries
gilters large amounts of fluid from the blood
covered by epithelial cells
encased in the bowman’s capsule
what is the role of tubule in nephron?
converts filtered fluid into urine
where does fluid filtered by glomerular capillaries flow into first, then second and third?
bowman’s capsule
proximal tubule
loop of henle
what does each loop of henle consist of and what are each of their walls like?
descending limb= thin
ascending limb= thick
what is at the end of the ascending limb?
short segment with a wall of plaque of specialized epithelial cells= macula densa
where does fluid go after the macula densa, which is followed by what 3 structures before being transported through what into what?
enters the distal tubue
then connecting tubule, cortical collecting tubule and collecting duct
transports through the pyramids to the real pelvis
what are two categories of nephron structures and what are their differences dependent on?
cortical nephrons
juxtamedullary nephrons
depending on how deep they lie within the kidney
what are two structural components of cortical nephrons?
have glmeruli located in the cortex
have short loops of Henle that penetrate only a short distance into the medulla
what % of neurons are juxtamedullary and what are two structural components?
20-30%
lie deep in the cortex near the medulla
have long loops of Henle that dip deeply into the medulla
what is the cortical nephrons surrounded by?
an extensive network of peritubular capillaries
what extends from juxtaglomerular nephrons and where do they extend to?
long efferent arterioles from the glomeruli into the outer medulla
what do the efferent arterioles of the juxtaglomerular nephrons divide into, what do they lie next to and where do they empty?
divide into specialized peritubular capillaries= vasa recta
extend down into medulla, next to loops of Henle
returns towards the cortex and empty into the cortical veins
what is the role of the specialized network of capillaries in the medulla?
formation of a concentrated urine
what does urine formation a result of? (4)
glomerular filtration
tubular reaborption
tubular secretion
excretion
what are the 2 main parts of the lymphatic system, and what are included in each part?
vessels: capillaries, collecting vessels, trucks & ducts
Tissues & organs: tonsils, thymus, spleen, peyer’s patches, appendix. circulating lymph
what are 3 functions of the lymphatic system?
fluid balance
fat absorption
immunological defense
what are 2 methods that the lymphatic systems controls fluid balance?
transports excessive interstitial fluid back to the blood circulation
controls interstitial fluid protein concentration, volume & pressure
how does the lymphatic system absorb fat?
absorbs & transports digested fat from chyle from the digestive system
transports in the nodes to the blood circulation to be processed by the liver
what are 3 methods that the lymphatic system is involved wit immunological defense?
macrophages carry foeign bodies, microbes & cancerous cells towards the lymph nodes, to be destroyed
lymphocytes in the nodes monitor lymph for antigens and mount an attack against them
filtration
