Physiology Flashcards
Roles of the Pulmonary (Respiratory) system?
Roles of the Pulmonary (Respiratory) system
- *1) Regulate plasma levels of oxygen and carbon dioxide** (most important)
- *2) Regulate plasma pH**
3) Protect against inhaled pathogens
4) Provide an adequate surface for gas exchange with the external environment
5) Assure adequate alveolar air movement by alterations in rate and depth of ventilation
6) Support vocalization of sound
Why makes the interpleurral space?
Lungs have tendancy to collapse, ribs have tendancy to expand.
At rest, diaphragm is__________
relaxed
When inhaling, the diaphragm _________ and thoracic volume ________.
diaphragm contracts, thoracic volume increases
When exhaling, the diaphragm _______, and thoracic volume ________
relaxes, volume decreases
Does length of trachea, etc affect air resistance?
yes, but it’s a constant; unaffected by other things
[higher pressure gradient, higher flow
higher resistance, lower the flow]
read others on picture
what mediates bronchoconstriction?
parasympathetic neurons
histamines
leukotriens
what factors affect bronchodilation?
carbon dioside
epinephrine
(want to dilate lungs in fear rxn…)
what happens if intrapleural space is invaded? (pneumothorax)
lung collapses
VT=
tidal volume
normal volume of air displaced when breathing normally
about the same in men and women
What is ERV?
expiratory reserve volume
amount of air that can be expired from the lungs by deterined effort after normal expiration
greater in men than in women
IRV =
inspiratory reserve volume
additional amount of air you can breath in
What is inspiratory capacity?
IRV + VT
RV?
residual volume - can’t move it out of lungs
What is the difference between capacities and volumes?
capacities are sums of 2 or more volumes
What is eupnea?
normal quiet breathing
What is hypernea?
increases respiratory rate and/or vol. in response to increase metabolism
(like exercise)
What is hyperventilation?
increased respiratory rate and/or vol. without increased metabolism
(panic attack, blowing up a balloon)
What is Hypoventilation?
decreased alveolar ventilation
shallow breathing, asthma
what is Tachypnea
rapid breathing; usually increased respiratory rate with decreased depth
ie panting
what is dyspnea
difficulty breathing
various pathologies or hard exercise
what is apnea?
cessation of breathing
voluntary breath-holding, depression of CNS control centers
Define Hypoxic hypoxia
low arterial PO2
high altitude; alveolar hypoventilation, decreased lung diffusion capacity; abnormal ventilation-perfusion ratio
define anemic hypoxia
decreased total amount of O2 bound to hemoglobin
blood loss, anemia (low {Hb] or altered HbO2 binding); carbon monoxide poisoning
Define ISchemic hypoxia
reduced blood flow
heart failure (whole-bpdy hypoxia); shock (peripheral hypoxia) thrombosis (hypoxia in a single organ)
define histoxic hypoxia
failure of cells to use O2 because cells have been poisioned
cyanice and other metabolic poisons
What regulates ventilation?
**peripheral chemoreceptors **
located in carotid and aortic arteries
specilzed glomus cells
sense changes in PO2, pH, and PCO2
centeral chemoreceptors
changes in CO2
What happens when PO2 decreases?
carotid body oxygen sensor releases neurotransmitter
(K+ channels close, cell depolarizes, voltage-gated Ca2+ channel opens, Ca2+ enters, neurotransmitters undergo exocytosis, reach receptor on sensry neuron, cause aciton potential)
What monitors CO2 in cerebrospinal fluid?
central chemoreceptors
What are the “controlled variables” that influence pulmonary function?
plasma levels of oxygen, carbon dioxide, and pH - it responds to increases plasma PCO2 and decrease PO2
Negative feedback essential for homeostatic regulation
change in co2 or o2 invfluence
What are the roles of the Renal system?
Kidneys:
1) Regulate extracellular fluid volume and blood pressure
2) Regulate osmolarity
3) Maintain ion balance
4) Regulate pH
5) Excrete waste
6) Produce hormones
histology of the kidney:
list outside to inside?
capsule
then cortex
then medulla where the filtering part extend through medulla and cortex before filtering out thru ureters
What are the critical parts of the kidney?
Nephrons:
short loops, long loops…filtrate passes through and is altered in various ways. After comes up into cortex, the tubule goes all the way thru the medulla and dumps nuron into renal pelvis
Bowman’s capsule is characterized by:
an inflow arteriole called the affarent arteriole. Remember they have ability to change their diameter (site of resistance). (If it constricts, less gets through, less filtration)
also has outflow arteriole - the efferent arteriole (if that constricts, forces more filtration.)
blood then goes into another capillary bed near the medulla - a portal where it particpates in absorbing the fluid that comes through the lopps and ducts.
180 L filtered a day.
What does the urinary excretion of a substance depend on?
on its filtration, reabsorption, and secretion
“clearance” = how much blood is cleared of a substance
What is special about glucose filtration?
it has special transporters to bring it back to blood - it’s reabsorbed, not gotten rid of
transporters can be overwhelmed (at 300 mg/100mL plasma) and sugar will spill over into urine - at the renal threshold
What do the secretory cells of the gastic mucosa do?
read all
How are long and short reflexes in the digestive system integrated?
it’s controlled by autonomic nervous system, but affected by somatic nervous system
Reflexes invovlving GI Peptides
Summarize motility, secretion, digestion, and absorption in different regions of the digestive system
*note: some absorption DOES happen in oral cavity
