Lecture 5 Flashcards
metabolic controls = local
signals =
declining O2 levels in tissues
inc levels of Co2, adenosine, H, K, heat, inflammatory chemicals
result =
immediate increased blood flow to needy tissues
called hyperemia = inc blood flow in rxn to having restricted blood flow or blockage
active vs reactive hyperaemia
signals are the same, causes are diff
reactive hyperaemia,
sitting legs crossed, foot foes to sleep, bc compressing vessels and bc sitting still so reducing blood flow, less O2 and inc waste buildup
when uncrossed and starts moving, inc blood flow, waste is removed and normal levels of O2 is reset
Active hyperimia
redistributing bloodd + inc CO (ml/min)
when physically active, lots of blood goes to skeletal muscles + head
less blood to unneccesay things
myogenic controls = local
signal = changes in body positions
bending over = blood rushed to brain = so constriction
vessels are stretched so constrict to resist inc flow to blood
stand back up = opposiite
decreased stretch so vessels dilated to encourage flow back up to Brian
result = cell perfusion homeostasis so cells aren’t deprives in response to low bp and not damages in response to high bp
making immediate adjustments when changing body orientation
forces that influences capillary exchange
cells are extremely close to a cap so nothing needs to travel far
walls are super thin, support a mix of diffusional, osmotic and hydrostatic forces
vesicle transpot
for larger, lipid insoluble molecules,
endocytosis then exocytosis
diffusion
for dissolved solutes nad gases
follows conc gradient
heat moves through thermal gradient, via convection
o2, co2, glucose,
bulk flow
esp imp for fluid movement
carry nutrients and waste in appropriate direction,
hydrostatic P
due to fluid pressing against a barrier,
HP pushes fluid across a border
in vessels, bc of blood pressurem
osmotic pressure
plasma proteins in capillaries create a gradient
water travels from few solute to many solute solutions
really (high water to low water)
it follows its gradient
OP pulls fluid back to caps/blood
net filtration at arteriolar end of a capillary
HP in caps pushes fluid out of cappilarory due to bp
Osmotic pressure inc aps pulls fluid into capillary due to osmotic gradient formed by plasma protein in blood
minimal/no HP in interstitial fluid, pushes fluid back into caps
a little bit of OP pulls fluid into interstitial fluid nad out of caps
NFP = net filtration pressure is (+) bc pushing fluid out
net filtration at venous end of a capillary
OP in caps, HP in IF, and OP in IF is all the same,
only HP in caps has changed
= decreased bc some fluids has gone out and remaining fluid and formed elements have encountered resistance in going through the cap bed so slower and less bp to push as forcefully
NFP is (-) bc pulling more in than pushing outd
difference in absolute NFP
arterioles was 10, venous was 8
so 1-2 mmH deficit
some fluid is lost to tissues and aren’t being pulled back by venous end of caps
so has to eb returned to circa system by lymphatic system,
special cases with the lymphatic sys
hypertension = inc bp
thrfr inc arteriole pressure
inc filtration pressure
inc pressure pushing fluid out at arteriole and venous end of caps
so more fluid loss to tissue
can cause edema = too much fluid in cells, lymphatic sys can get overwhelemed
hemmorage = significant blood loss
favors reabsoltiopn,
so leave less behind and reabsorb more
lymphatic system
2 parts = lymphatic vessels + lymphatic tissues/organs
kinda like 2nd half of circa system
lymphatic vessels in gen
return leaked fluid and plasma proteins back to blood sream.
lymphatic tissue or organs in gen
essential in body to provide defence/resisitance to disease
blood/fluid/caps could have debris, cancerous cells, tumour cells, micro orgs,
so as picked up sent to organs for inspection by immune sys to remove/kill undesirable substances
not perfect, cancerous cells can take adv of the system to get to blood stream and grow
lymphatic vessels description, where found, permeability
begin w microscopic closed ended capillaries
everywhere but ones, teeth, bone marrow and limited in CNS
close ended to leakier than vessels in circulation sys
very permeable
1. flap like mini valves provide space in bn loosely att endothelial cells
allow movement of fluids and can pick up any “lost plasma proteins” + can pick up and debris, micro org or cancer cells
- collagen filaments anchor endothelial cells to surr tissues bc origin isn’t held in place
lymph bodes, what, where, roles
clusters along lymph vessels
larger clusters the many vessels converge
inguinal, axillary and cervical regions
filter, remove and destroy micro orgs
activate immune system if anything is found
right lymphatic duct vs thoracic duct
RL duct = right side of head, right arm, right side of chesr
TD = left head, neck and chest, entire body below
Lymphoid cells
what they are + 4 types
immune system cells + supporting cells
lymphocytes:
Macrophages
Dendritic
Reticular cells
lymphocytes
T cells = soldiers - cell/cell attack infected/cancerous cells
B cells = can differentiate into antibody-producing plasma cells
macrophages
phagocytic foreign substance and are antigen presenters
pick up bits and pieces of pathogens, dispel on cell surface to initiate/activate a immune system response against the threat.
Dendritic
also antigen presenters, bring antigens to lymph nodes from skin and mucosal linings
reticular cells
fibroblast like cells that produce extracellular matrix that supports immune cells
