Sweep 1 Flashcards
Enteric Nervous System
submucosal and myenteric nerve plexuses
e.g., CCK stimulated by ———, stimulates ——— by pancreas, which will reduce CCK and reduce pancreas activation.
fatty acids
enzyme production
e.g., CCK can stimulate pancreas, liver, gallbladder, and inhibit ——–
stomach emptying
Cephalic Phase
(parasympathetic nerve fibers affecting ENS)
Gastric Phase
(short and long neural reflexes and gastrin)
Intestinal
(short and long neural reflexes, secretin, CCK, and GIP)
Gastrin—G Cells
Antrum (Pyloric Gland Area)
Somatostatin—D cells
Throughout the stomach at the base of the gastric glands
Histamine is the strongest
HCl stimulant.
Histamine release can be triggered by
gastrin or Ach
Gastrin and Ach can have direct effects on
parietal cells.
Somatostatin is a potent inhibitor of HCl secretion via 2 mechanisms
Effects on G Cell
Effects on Parietal Cell
Enterogastrone is a hormone produced by ——- that inhibit the ——– in the stomach. Secretin, and CCK are enterogastrones.
intestinal cells
secretion or motility
Parasympathetic stimulation releases —— onto the —— and results in a ————-.
ACh
acinar cells
watery plasma-like secretion
Acetylcholine Primarily (some effect of Norepinephrine via α-adrenergic receptor)
Opening of Ca++ sensitive Cl- and K+ channels
Increased flow rate, lowered ductal modification
Muscarinic or α-adrenergic
Norepinephrine
Protein rich saliva
PKA-mediated exocytosis
β-adrenergic receptor
Lungs
e.g. convert
angiotensin I to angiotensin II
Cystic fibrosis is a disease that
impairs the normal function of the conducting zone
Cystic fibrosis
mutation in genetic code for
Cl- channel reduces the amount of Na+ and Cl- secreted across the epithelium into mucus.
Cystic fibrosis
This leads to there being
less water in the mucus (due to osmosis)→ mucus is thick and dry
Between breaths:
Pip —— atmospheric pressure
below
Between breaths:
Ptp =
Palv – Pip; lungs remain expanded
lungs tend to recoil inward –
chest wall tends to recoil outward –
net result is Pip is always subatmospheric
During inspiration
Pip becomes
more negative
During inspiration
Ptp increases so
lung volume increases and air flows in until Palv = Patm
During expiration -
Pip becomes
less negative
During expiration -
Ptp decreases so
lung volume decreases and air flows out until Palv = Patm
Closed pneumothorax
pleural cavity pressure less than atm
open pneumothorax
pleural cavity pressure is atm
tension pneumothorax
pleural cavity pressure greater than atm
Compliance is the inverse of
stiffness, and is indicative of the amount of muscle force needed to ventilate the lung.
Forces are strong on the ——, but weak on the —— side.
liquid side
air
Surface tension (ST) in bubbles cause the liquid lining to be
pulled toward the center (note that in a bubble there are two air/liquid interfaces).
Surfactant is an
amphipathic phospholipid + protein molecule that forms a monolayer between air and water.
Reduces surface tension by
decreasing
density of H2O molecules
Surfactant does not create
additional surface tension and will increase compliance.
transpulmonary pressure – dilates
bronchioles during inspiration
increase R
breathe
more deeply (to increase ΔP)
Increase R
breathe more slowly because
airflow during expiration is limited
decrease compliance
breath shallowly to decrease
muscle involvement
inspiratory reserve volume (IRV) –
max V inspired ; ~3000 ml
tidal volume (TV) –
V entering lungs per breath; ~500 ml
expiratory reserve volume (ERV) –
V exhaled beyond TV; ~1500 ml
obstructive lung disease:
↓ FEV1; normal VC
restrictive lung disease:
↓VC, normal FEV1
Alveolar dead space exists when there is a mismatch between
ventilation and bloodflow
Alveolar dead space is always
greater than zero, even in normal lungs, due to the effects of gravity on bloodflow
Hypoventilation – ventilation
decreased relative to metabolism
decrease alveolar PO2
increase alveolar PCO2
Hyperventilation – ventilation
increased relative to metabolism
increase alveolar PO2
decrease alveolar PCO2
