Midterm #2 Flashcards
1
Q
also called white blood cells
A
leukocytes
2
Q
only formed elements that are complete cells, with nuclei and the usual organelles
A
leukocytes
3
Q
form a mobile army that helps to protect the body from damage by bacteria, viruses, parasites, toxins, and tumour cells
A
leukocytes
4
Q
special characteristic of leukocytes
A
able to slip out of capillary blood vessels
5
Q
diapedesis
A
ability of leukocytes to slip out of capillaries
6
Q
what uses signals to prompt WBCs to leave the bloodstream at certain locations
A
cell adhesion molecules displayed by endothelial cells forming the capillary walls at sites of inflammation
7
Q
how do leukocytes move through the tissue space once out of the bloodstream
A
through a process called amoeboid motion
8
Q
positive chemotaxis
A
leukocytes follow the chemical trail of molecules released by damaged cells or other leukocytes and pinpoint areas of tissue damage and infection and gather there in large numbers to destroy foreign substances and dead cells
9
Q
leukocytosis
A
WBC count over 11 000 cells/µL
(normal response to an infection in the body)
10
Q
what are the 2 major categories that leukocytes are grouped into and what are they based on?
A
grouped based on structural and chemical characteristics
granulocytes and agranulocytes are the 2 categories
11
Q
rank leukocytes from most abundant to least abundant
A
neutrophils
lymphocytes
monocytes
eosinophils
basophils
“never let monkeys eat bananas”
12
Q
3 types of granulocytes
A
neutrophils
eosinophils
basophils
13
Q
properties of granulocytes
A
- roughly spherical
- larger
- lobed nuclei
- much shorter-lived than erythrocytes
- membrane-bound cytoplasmic granules stain specifically with Write’s stain
14
Q
most numerous WBC (50-70% of population)
A
neutrophils
15
Q
twice as large as erythrocytes
A
neutrophils
16
Q
cytoplasm contains very fine granules that are difficult to see
A
neutrophils
17
Q
cytoplasm takes up both basic and acidic dyes and together give the cytoplasm a lilac colour
A
neutrophil
18
Q
lysosomes
A
neutrophil granules that contain hydrolytic enzymes
19
Q
defensins
A
smaller neutrophil granules that contain a potent ‘brew’ of antimicrobial proteins
20
Q
polymorphonuclear leukocytes
A
neutrophil nuclei that have 3-6 lobes
21
Q
the body’s bacteria slayers
A
neutrophils
22
Q
when do neutrophil numbers increase explosively?
A
during acute bacterial infections
23
Q
which leukocyte is chemically attracted to sites of inflammation and are active phagocytes
A
neutrophils
24
Q
how do neutrophils ingest bacteria and some fungi?
A
enclose them in a vesicle called a phagosome
25
what is a respiratory burst?
- a method by which neutrophils can kill bacteria
26
how does s respiratory burst work?
- cells metabolize oxygen to produce potent germ-killer oxidizing substances such as bleach and hydrogen peroxide
- defensin containing granules merge with the microbe containing phagosome and form peptide 'spears' that pierce holes in the membrane of the ingested 'foe' and the bacterium lyses
27
makeup 2-4% of leukocytes and are about the size of neutrophils
eosinophilis
28
describe the granules found in eosinophils
- large, coarse granules that stain from brick-red to crimson with acid dyes pack the cytoplasm
- lysosome-like and filled with a unique variety of digestive enzymes but unlike lysosomes, they lack enzymes that specifically digest bacteria
29
the most important role of eosinophils
lead the counter-attack against parasitic worms that are too big to be phagocytized
30
where do eosinophils reside?
in the loose connective tissues and when they encounter a parasitic worm, they gather around and release the enzymes from their cytoplasmic granules onto the parasites surface, digesting it away
31
have complex roles in many other diseases including allergies and asthma
eosinophils
32
contribute to tissue damage that occurs in many immune processes but are important modulators of the immune response
eosinphils
33
rarest WBC (0.5-1%)
basophils
34
cytoplasm contains large, coarse, histamine containing granules that have an affinity for the basic dyes and stain purplish black
basophils
35
inflammatory chemical that acts as a vasodilator and attracts other WBCs to the inflamed site
histamine
36
nucleus is usually U or S-shaped with 1 or 2 constrictions
basophils
37
granulated cells similar to basophils, found in connective tissues
mast cells
38
both basophils and ____ bind to a particular antibody that causes the cells to release histamine
mast cells
39
- include lymphocytes and monocytes
- WBCs that lack visible cytoplasmic granules
- nuclei are typically spherical or kidney shaped
agranulocytes
40
how do the kidneys maintain the body's internal environment?
- by regulating the total volume of water in the body and the total concentration of solutes in that water (osmolarity)
- by regulating the concentrations of various ions in the extracellular
- by ensuring long-term acid-base balance
- by excreting metabolic wastes and foreign substances such as drugs or toxins
- producing erythropoietin and renin, important molecules for regulating red blood cell production and blood pressure, respectively
- converting vitamin D to its active form
- carrying out gluconeogenesis during prolonged fasting
41
ureters
paired tubes that transport urine from the kidneys to the urinary bladder
42
urinary bladder
a temporary storage reservoir for urine
43
urethra
a tube that carries urine from the bladder to the body exterior
44
renal hilum
leads into the renal sinus
45
the 3 layers of supportive tissue surrounding each kidney (from superficial to deep) are:
- renal fascia
- perirenal fat capsule
- fibrous capsule
46
renal fascia
outer layer of dense fibrous connective tissue that anchors the kidney and the adrenal gland to surrounding structures
47
perirenal fat capsule
fatty mass that surrounds the kidney and cushions it against blows
48
fibrous capsule
transparent capsule that prevents infections in surrounding regions from spreading to the kidney
49
renal cortex
- most superficial region of kidney
- light coloured
- has granular appearance
50
renal medulla
- dark, reddish brown
- has cone-shaped tissue masses called medullary (or renal) pyramids
51
medullary (or renal) pyramids
- appear striped
- formed almost entirely of parallel bundles of microscopic urine collecting tubules and capillaries
52
renal columns
- inward extensions of cortical tissue
- separate the pyramids
53
renal pelvis
- funnel-shaped tube
- continuous with the ureter leaving the hilum
- branching extensions form calyces
54
renal arteries
- large
- deliver 1/4 of the total cardiac output to the kidneys (~1200 mL each minute)
55
calyces
collect urine, which drains continuously from the papillae, and empty into the renal pelvis
56
path of blood flow through the renal blood vessels
aorta - renal artery - segmental artery - interlobar artery - arcuate artery - cortical radiate artery - afferent arteriole - glomerulus - efferent arteriole - peritubular capillaries or vasa recta - cortical radiate vein - arcuate vein - interlobar vein - renal vein - inferior vena cava
57
renal plexus
- network of autonomic nerve fibres and ganglia
- provides the nerve supply of the kidney and its ureter
- largely supplied by sympathetic fibres from the most inferior thoracic and first lumbar splanchnic nerves
58
how do sympathetic vasomotor fibers regulate blood flow?
by adjusting the diameter of renal arterioles and also influence the formation of urine by the nephron
59
nephrons
the structural and functional units of the kidneys
60
what do nephrons do?
- create cell- and protein-free filtrate from blood
- from that filtrate, recovers chemicals needed by the body while also secreting into that filtrate selected chemicals the body needs to get rid of
- nephrons empty their processed filtrate into collecting ducts
61
what happens in the glomerulus?
- endothelium of capillaries is fenestrated, which makes capillaries exceptionally porous
- large amounts of filtrate pass from blood into glomerular capsule
62
filtrate
- solute-rich but virtually protein-free fluid
- raw material that the renal tubules process to form urine
63
glomerular capsule
- has an external parietal layer and a visceral layer that cliings to the glomerular capillaries
64
parietal layer of the glomerular capsule
- made up of simple squamous epithelium
- contribute to capsule structure but plays no part in forming filtrate
65
visceral layer of the glomerular capsule
- clings to the glomerular capillaries
- consists of highly modified, branching epithelial cells called podocytes
66
podocytes
- highly modified, branching epithelial cells
- have foot processes that cling to the basement membrane of the glomerulus
67
filtration slits
openings between the foot processes
68
filtrate enters the ___ through the filtration slits
capsular space
69
renal tubule
~3 cm long
- 3 major parts: proximal convoluted tubule, nephron loop, distal convoluted tubule
- meandering nature increases its length and enhances its filtrate processing capabilities
70
proximal convoluted tubule
- walls are formed by cuboidal cells with large mitochondria
- apical surfaces bear dense microvilli
71
nephron loop
- has ascending and descending limbs
- proximal part of descending limb is continuous with the proximal convoluted tubule
- rest of descending limb is called descending thin limb
- ascending part of loop called thick ascending limb
in some nephrons, thin segment extends around the bend and is called thin ascending limb
72
distal convoluted tubule
- epithelial cells are cuboidal and confined to cortex but are thinner and almost entirely lack microvilli
73
collecting duct
- contains 2 cell types
- principal cells have sparse, short microvilli and are responsible for maintaining the body's water and Na+ balance
- intercalated cells are cuboidal with abundant microvilli
- 2 varieties of intercalated cells (A & B) and each plays a role in maintaining the acid-base balance of blood
74
glomerular filtration
- passive and nonselective
- fluids & solutes are forced through by capillary hydrostatic pressure
75
why is the glomerulus an efficient filter?
- filtration membrane is 1000x more permeable than any other capillary membranes
- glomerular blood pressure higher than in other capillary beds
76
3 layers between blood & interior of glomerular capsule
- fenestrated capillary endothelium
- basement membrane
- visceral membrane of glomerular capsule = foot processes of podocytes
77
molecules ≤ 3 nm
- water, glucose, amino acids, nitrogenous wastes
- pass easily
78
molecules 3-5 nm
- pass, but with greater difficulty
79
molecules ≥ 5 nm
- usually not filtered
80
calculate net filtration pressure (NFP) when
HP gc = 55 mm Hg
OP gc = 30 mm Hg
Hp cs = 15 mm Hg
NFP = net filtration pressure
= outward pressures - inward pressures
= (HP gc) - (HP cs + OP gc)
= 55 - (15 + 30)
= 10 mm Hg
81
define net filtration pressure
- pressure responsible for filtrate formation
- HP gc = pushes out of blood
- OP gc = pulls back into blood
- HP cs = pushes back into blood
82
glomerular filtration rate (GFR)
= total amount of filtrate formed per minute by both kidneys (~125mL/min)
83
GFR depends on:
- total surface area for filtration
- filtration membrane permeability
- net filtration pressure
GFR IS DIRECTLY PROPORTIONAL TO NFP
84
3 regulatory influences on GFR
- renal autoregulation (intrinsic)
- neural controls (extrinsic)
- renin-angiotensin system (extrinsic)
85
intrinsic mechanism: renal autoregulation
- kidney keeps GFR ~constant by determining its own rate of flow & adjusting nephron blood flow
- regulates diameter of afferent (primarily) and efferent arterioles
- myogenic mechanism
- tubuloglomerular feedback mechanism
- can maintain ~constant GFR with 80-180 mm Hg systemic bp
- if systemic bp drops below 80 mm Hg (hypovolemic shack) renal autoregulation & filtrate formation shut down and extrinsic regulation kicks in
86
myogenic mechanism
- responds to any change in bp of blood vessels
- focus = afferent arteriole
87
tubuloglomerular feedback mechanism
- directed by macula densa cells of JGC
- monitoring NaCl content of filtrate
- high osmolarity of fast-flowing filtrate: release vasoconstrictor
low osmolarity of slow flowing filtrate: allow vasodilation by releasing less ATP
88
neural controls
- in times of extreme stress, SNS overrides renal autoregulation & shunts blood to the heart, brain, skletal muscles at the expense of the kidneys
- direct sympathetic-induced vasoconstriction of afferent arterioles
89
renin-angiotensin mechanism
- involved in renal regulation, but its main purpose is to stabilize systemic blood pressure & ECF volume
can be activated by:
- direct stimulation of granular cells by the SNS to secrete renin
- macual densa cells stimulate granular cells to secrete renin when they sense reduced filtrate osmolarity, reduced flow
- reduced stretch of granular cells directly induces release of renin
90
angiotensin II
- potent, generalized vasoconstrictor
- stimulates release of aldosterone by the adrenal cortex; aldosterone stimulates reabsorption of Na+, water follow if water channels are open
- afferent arterioles have fewer angiotensin receptors than the efferent arterioles
-
91
general principles of reabsorption
- organic nutrients (glucose, amino acids) ~ 100% reabsorbed
- reabsorption can be active or passive
- rate/degree of reabsorption of H2O/ions hormonally adjusted
92
active tubular reabsorption
- usually substances are moved against electrical and/or chemical gradient
- active process atlevel of basolateral membrane: substance moves passively into tubule cell, but only because sodium actively transported into the interstitial space to maintain the gradient
- glucose, amino acids, lactate, vitamins, ions are actively reabsorbed
- transport systems (carriers) fairly specific; have transport maximum (Tm)
- when carriers are saturated, excess of substance appears in urine
- plasma proteins: if squeeze through, taken up by tubule cells; hydrolyzed & amino acids to blood
