Unit 5 Flashcards
1
Q
Name 5 functions of blood vessels
A
- Allow exchange of gases
- Carry nutrients to tissue
- Carry metabolic wastes away
- Carry hormones and signaling substances
- Maintain quality and quantity of tissue fluid
2
Q
Conducting arteries
A
Larger, allow rapid blood flow and have elastic laminae to help smooth out pressure differences w/ distance from the heart
3
Q
Distributing arteries
A
Medium, have slower blood flow and flow can be controlled by regulatory factors like chemical/neural input to regulate flow to different organs
4
Q
Tunica intima
A
Innermost of the 3 concentric layers surrounding blood vessel lumen: endothelium, basal lamina and a subendothelial layer of loose connective tissue that may have some smooth muscle cells. Main function: permeable/semi-permeable barrier
5
Q
Tunica media
A
Middle of the 3 concentric layers surrounding blood vessel lumen: composed of smooth muscle and varying amounts of elastic fibers and lamellae, reticular fibers and proteoglycans. Main function: controls diameter, blood pressure and movement.
6
Q
Tunica advemtitia
A
Outermost of 3 concentric layers surrounding blood vessel lumen: composed of fibroblasts, longitudinally oriented T1 collagen and elastic fibers. Main function: physical support, attach vessel to tissue, carry vessels and nerves
7
Q
Vasa vasorum
A
Found in adventitia and media of larger blood vessels, it provides nutrients via small vessels to the vessel wall, vessel inside a vessel,
8
Q
Veins or arteries have a more extensive vasa vasorum?
A
Veins do, they need more small vessels providing nutrients bc of the low nutrient and oxygen content of venous blood.
9
Q
Endocardium
A
Homoglous to intima of blood vessels, lines atria and ventricles, composed of endothelium and subendothelial layer of connective tissue
10
Q
Myocardium
A
Homologous to media of blood vessels, thickest layer of heart wall, composed of cardiac muscle that is thicker than the ventricles than in the atria
11
Q
Epicardium
A
homologous to adventitia of blood vessels, forms surface of the heart and is defined as the visceral layer of the pericardium. Composed of mesothelium and subepicardial layer of loose connective tissue that contains nerves, adipose tissue and coronary blood vessels
12
Q
Name some elastic arteries
A
Aorta and its main branches, common carotid, brachiocephalic, subclavian and pulmonary arteries
13
Q
What happens to elastic arteries during systole and diastole?
A
During systole (heart contraction) the elastic arteries are distended, then they recoil and contract during diastole. This produces a more uniform flow and pressure.
14
Q
Describe mixed musculo-elastic arteries
A
They form parts of the terminal abdominal aorta, the iliac arteries, external carotids, axillary arteries. They are transitional b/w large and medium arteries. Tunica media and adventitia are about the same thickness, media has less elastic lamallae and there’s a more obvious internal elastic membrane
15
Q
Give examples and functions of the medium, muscular, distributing arteries
A
Coronary, renal, mesenteric, brachial femoral. They distribute blood to tissues and organs regulated by autonomic nervous system control of the media
16
Q
Histology of large, elastic, conducting arteries
A
Thin adventitia with nerve fibers, lymphatics and vasa vasorum in loose connective tissue
17
Q
What is the function of large, elastic, conducting arteries?
A
To produce uniform flow and pressure by distending during systole and recoiling/contracting during diastole
18
Q
Histology of medium, muscular, distributing arteries
A
Thin intima with prominent internal elastic lamina that undulates, thick media composed of concentric layers of smooth muscle cells bounded in larger muscular arteries by an external elastic lamina, adventintia can be as thick as media, with poorly developed vasa vasorum and lymphatics
19
Q
Describe arterioles
A
Invisible to naked eye, function to maintain normal BP in the arterial system and to reduce pressure of blood entering capillaries
20
Q
How do arteries change with age?
A
After age 30 the media becomes stiffer due to inc in elastic lamellae and deposition of collagen and proteoglycans
21
Q
Atherosclerosis
A
thickening and hardening of the walls of arteries caused by plaques that form in the intima as a consequence of chronic inflammatory disease. Plaque formation is initiated by fat (LDL) accumulation in macrophages called foam cells.
22
Q
Endothelial cells
A
Non-thrombogenic, secrete basal lamina, jointed by tight (occluding) and gap junctions, slow renewing
23
Q
Pericytes
A
Stellate cells with extensive branching that surround capillaries, they share basal lamina of endothelial cells. They can contract to regulate blood flow and serve as stem cells for endothelial and smooth muscle cells after injury
24
Q
What is the function of continuous Capillaries
A
They have complete basal lamina and endothelial lining - sealed by tight junctions that allow the passage of small molecules. Also have vesicles in cytoplasm to transport large molecules.
25
Where are fenestrated capillaries found?
Found in the pancreas, intestines and endocrine glands. A special type with no diaphragms are found in the renal glomerulus.
26
Where are continuous capillaries found?
Found in muscle, nervous and connective tissue.
27
What is the function of fenestrated capillaries?
Rapid interchange of substances b/w blood and tissue
28
What are sinusoids and what are the 3 types of sinusoids?
Irregular blood channels that conform to the shape of the structure they line.
1. Sinusoidal capillaries (endocrine glands)
2. Discontinuous sinusoids (liver and bone marrow)
3. Venous sinusoids (spleen)
29
Two types of capillary permeability
1. Small pores - gaps b/w cell junctions that allow water and small hydrophilic molecules to pass
2. Large pores - allow transcytosis by pinocytosis or trans-golgi derived vesicles
30
Veins morphologically compared to arteries
Larger caliber, more numerous (contain 70% of total blood volume), more variable in size and structure, more extensive vasa vasorum and lymphatics, more collagen, less elastic substance and smooth muscle
31
What is the largest tunic in veins?
The adventitia is the largest and best developed tunic, forming 95% of the thickness of vein's walls.
32
Structure of large veins
Intima - continuous endothelium and basal lamina, no internal elastic lamina
Media - often incomplete or absent
Adventitia - largest and best developed, thick bundles of longitudinal smooth muscle, collagen and elastic fibers, vasa vasorum and lymphatics
33
Structure of small and medium veins
Intima - continuous endothelium and basal lamina, complete internal elastic laminae found in leg veins
Media - poorly developed except in limbs
Adventitia - thickest tunic, made of collagen layers and elastic fibers with fibroblasts, vasa vasorum and lymphatics, usually has no smooth muscle
34
Name the two classes and functions of venules
Pericytic (post-capillary venules, resmble capillaries) and muscular (receive blood from pericytic venules and accompany arterioles)
They continue the exchange of materials that was started in the capillaries. Preferred location for leukocyte emigration and become leaky in response to histamine and serotonin.
35
What do portal systems do and what are some examples?
Carry blood from one capillary bed to another. Hepatic portal vein between intestines and the liver. Hypophyseal portal veins of the pituitary. Efferent arterioles of the renal cortex.
36
What connects arterioles and venules and how do they work?
Atriovenous anastomoses are direct cross connections b/w arterioles and venules. Smooth muscle cells form a sphincter that regulates blood flow and allows a bypass of a capillary bed.
37
What are some characteristics of lymphatic vessels?
Large lumens
Thin walls
Irregular shapes (structurally similar to veins but more irreg)
Extensive branching running parallel to blood capillaries and veins
They have discontinuous or absent basal lamina and are held open by elastic anchoring filamens
38
What are the functions of lymphatic vessels?
Collect lymph from extracellular spaces and return it to the blood vascular system. Also aid in lymphocyte circulation.
39
How are inspiration and expiration achieved at rest?
Inspiration is actively achieved through contraction of the external intercostal muscles and the diaphragm. Expiration is passively achieved through the elastic recoil of connective tissue in the lungs and chest wall.
40
Why is inspired air filtered, warmed in humidified?
Inspired air is filtered, warmed and humidified in the conducting portions of the respiratory tract. Warmth and humidification enhance gas exchange when air reaches respiratory portion and prevent tissue damage due to cold air. Filtering prevents pathogens and/or irritants from reaching sensitive gas exchange regions.
41
What is the respiratory epithelium and where is it found?
The respiratory epithelium is a specialized mucosa that lines the resp tract from the upper nasal cavity to the bronchioles. It functions to filter, warm and moisten the air. It's composed of pseudo stratified columnar epithelium, interspersed with goblet cells.
42
What are the 5 cell types found in the respiratory epithelium?
1. Ciliated pseudo stratified columnar epithelial cells - most abundant, with cilia & basal bodies
2. Mucous goblet cells - mostly in trachea and larynx, extend from basement membrane to lumen, secrete polysacc-rich mucous drops
3. Brush cells - afferent nerve endings on base; surface, microvilli on apical surface that function as sensory receptors
4. Basal cells - regenerative - undergo mitosis to give rise to other types, short and rounded
5. Granule cells - may be part of neuroendocrine system to regulate mucus and serous secretion
43
Which 3 respiratory epithelium cell types sit on basement membrane and extend all the way to the lumen?
Ciliated psuedostratified columnar epithelial cells
Mucous goblet cells
Brush cells
44
Which 2 respiratory epithelium cell types sit on basement membrane but DO NOT extend all the way to the lumen?
Basal cells and granule cells
45
Muco-ciliary elevator
A layer of mucus secreted by goblet cells and seromucous glands floats on a more aqueous secreted layer that surrounds the beating cilia. Inhaled particles become trapped in the mucus. Coordinated action of the beating cilia propels mucus and particles across the aqueous layer towards to mouth/nose. Critical to host defense in the lungs.
46
Kartagener syndrome
Genetic disorder in which the protein dynein (responsible for microtubule sliding in cilia movement) is not functional or is absent. Frequent respiratory infections bc inhaled particles can't get cleared from the respiratory tract.
47
What changes as you move deeper into the respiratory tree?
Ciliated psuedostratified columnar epithelium-> ciliated simple cuboidal -> squamos (in alveoli) The amount of goblet cells, smooth muscle and cartilage decreases, while the amount of elastic fibers in connective tissue increases.
48
Are cilia or goblet cells found deeper in the respiratory tract and why?
Cilia are found deeper than goblet cells to prevent retrograde flow of mucus
49
What is the first host defense function in the respiratory system?
Vibrassae - nose hair - traps infectious particles upon inhalation
50
What is a meatus and how can you distinguish between the 3?
Space between the inferior middle and superior conchae that allows air passage and forces turbulent flow to humidify and warm air.
Inferior and middle are lined w/ respiratory epithelium
Superior is lined with olfactory epithelium (lacks cilia)
51
What are the cell types in olfactory epithelium?
Supporting cells - apical microvilli, apical nuclei
Olfactory cells - bipolar neurons, central nuclei
Basal cells - small, round, at base of epithelium
Olfactory/Bowman's glands - produce proteinaceous serous secretions to clear cilia and facilitate access of new odorants. Found in superior meatus, near olfactory epithelium.
52
What are paranasal sinuses?
Chambers in frontal, maxillary, ethmoid, sphenoid bones. Lined with respiratory ciliated epithelium, goblet cells, small glands. Connected to nasal cavity through small passages.
53
Pharynx
Tube connecting oral and nasal passages, lined primarily with respiratory epithelium dorsally and stratified squamous epithelium ventrally.
54
Larynx
Tube connecting pharynx and trachea, epiglottis prevents food from entering the trachea.
Hyaline cartilage support -- subject to ossification i.e.: with old age it loses flexibility and voice changes.
Skeletal muscle articulates the cartilage and permits phonation.
55
False and true vocal cords
Found in larynx.
False = vestibular folds, upper, serous glands in lamina propia -- keep vocal cords moist for protection
True = below vocal cleft, stratified (to protect from abrasion from high velocity air) squamous epithelium w/ vocal ligament and vocalis muscle -- voluntary skeletal muscle
56
Trachea
10 cm tube connecting larynx and bronchi, lined with respiratory epithelium, thick basement membrane, mixed glands with some elastic fibers,
16-20 incomplete regular rings of hyaline cartilage that hold it open
57
Bronchi
More malleable than trachea, cartilage is irregular rings or plates.
2 primary bronchi, one each to right and left lung (large)
5 branches of primary bronchi, 3 right and 2 left = lobar bronchi (large)
Smooth muscle in irregular bands, causes wavy/folded mucosa
58
Bronchioles, 2 types
Branches of small bronchi, transition between conductive and respiratory regions -- changes from respiratory ti cuboidal epithelium
NO CARTILAGE!
1. Regular -- ciliated columnar with goblet cells. Mucosa is wavy/folded due to post-mortem constriction of smooth muscle. Where most regulation of ventilation occurs due to large CSA, lack of cartilage and present smooth muscle,
2. Terminal -- non-ciliated columnar or cuboidal, may have a few cilia, goblet cells are replaced by Clara Cells. Mucosa is smooth, not wavy bc there's less smooth muscle.
59
What are Clara cells?
Found in terminal bronchioles instead of goblet cells. Tall cells that share the basement membrane with cuboidal epithelium and extend taller than the surrounding epithelium. Dense granules that contain protein, secreted along with aqueous solution to moisten the epithelium.
60
What are the 2 portions of the respiratory tract?
1. Conducting portion - made up of the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles; their function is to filter, warm, and moisten air and conduct it into the lungs.
2. Respiratory portion - site of gas exchange, made up of respiratory bronchioles, alveolar ducts
61
Respiratory bronchioles
Similar to terminal bronchioles, simple cuboidal or columnar epithelium with few cilia, no goblet cells, reduced levels of smooth muscle. Outpocketings of alveoli in bronchiole walls permit gas exchange.
62
Alveolar ducts
Passageway completely lines with alveoli, simple squamous epithelial lining, NO cilia, NO goblet cells, NO clara cells. Smooth muscle in cusps of alveolar openings allow for more regulation of ventilation
63
What is the diffusion pathway for gases?
Surfactant --> epithelium (2 membranes + cytoplasm) --> fused basement membrane composed of epithelial basal lamina and endothelial basal lamina --> endothelium (2 membranes + cytoplasm) --> red blood cell membrane
64
What is the alveolar septum?
A thin wall well-adapted for gas exchange between air and blood
65
What cell types are found in the alveolar septum?
Type I Pneumocyte/epithelium - 97% of surface area, but only 8% of number, thin flat squamous, forms vast majority of lung lining -- does most gas exchange
Type II Pneumocyte/epithelium - 16%, cuboidal, source of surfactant (dec surface tension to prevent alveolar collapse), regenerative, found at septal junctions
Capillary endothelial cells - 30%, very thin, crescent shaped nuclei, form capillary walls
Interstitial cells - 36%, fibroblasts and mast cells, alveolar macrophages: dust cells
66
What are alveolar pores?
Pores of Kohn that penetrate the alveolar wall, equalize air pressure b/w neighboring alveoli and promote collateral air circulation providing equal ventilation throughout the lung
67
What is the acellular interstitial?
Made of type 3 collagen, elastic fibers and proteoglycans. Critical for respiratory mechanics/passive exhalation
68
What is pleura?
Serous membrane covering the entire lung. Has parietal and visceral layers, each containing a mesothelium. The layers are fused at the hilum. The space between layers is fluid filled to permit lung movement.
69
2 parts of pulmonary circulation
1. Nutrient (systemic) - brings oxygen and nutrients to lung tissue, arterial supply found in submucosa
2. Functional (pulmonary) - pulmonary artery blood to be oxygenated, thin walled/low pressure side of circulation
70
Types of respiratory host defense
1. Acid Base Balance - regulate amount of carbon dioxide retained in body, important short term pH regulator
2. Metabolic - pulmonary capillary endothelium
3. Immunologic - cellular (vibrassae, muco-ciliary elevator, alveolar macrophages) and humoral (IgA and IgE, mast cells, BALT)
71
What are the major functions of the urinary system and which organ performs them?
Kidney
- Excretion of waste
- Maintenance of homeostasis via selective filtration and reabsorption of water and solutes
- Hormone production (renin for blood pressure regulation, erthypoietin, active form of vitamin D)
72
What are the post-renal excretory organs and what is their function?
Ureters, bladder, urethra
| Storage and excretion of urine
73
Hilum
Concave area of the kidney that contains nerves, ureters, blood and lymph vessels
74
Capsule
Dense, regular connective tissue surrounding the kidney.
75
Cortex
Outer layer of the kidney, contains renal corpuscles
76
Renal pelvis
Expanded upper portion of the ureter, divides into 2 or 3 major calyces, further divided into minor calyces
77
Medulla
Inner portion of the kidney, forms conical structures called conical structures called renal pyramids or medullary pyramids, with the tips of the pyramids forming renal papillae, opening up into the calyces of the renal pelvis. The pyramids are surrounded by the cortical tissue that reaches down to form renal columns, known as column of Bertin.
78
Medullary pyramids
Conical structures formed by the medulla. The tips of the pyramids form renal papillae, opening up into the calyces of the renal pelvis. The pyramids are surrounded by the cortical tissue that reaches down to form renal columns, known as column of Bertin, which separate each pyramid. Each pyramid joins with the cortex tissue at its base and forms a renal lobe.
79
Medullary ray
The medullary tissue reaches up into the cortex to form rays. A medullary ray and surrounding nephron that are associated with the same collecting duct = renal lobule
80
Nephrons
The functional units of the kidney, divided into 5 portions: renal corpuscle, proximal tubule, loop of henle, distal tubule, connecting tubule -- merge to form collecting ducts
81
Renal corpuscle
Formed by the Bowman's capsule plus the glomerulus. Site of selective water and solute filtration from blood, always found in cortex. Contain a tuft fenestrated capillaries called the glomerulus.
The corpuscle has 2 poles: vascular pole - where arterioles enter and exit, and urinary/tubular pole: where the proximal convoluted tubule exits the corpuscle, carrying the urinary filtrate.
82
Proximal tubule
convoluted - in cortex, straight - in medulla
83
Loop of Henle
in the medulla, includes thin descending and ascending limbs and thick ascending limb
84
Distal tubule
straight: ascending from loop of Henle back into the cortex
convoluted: in the cortex
85
Connecting tubule
merge with other connecting tubules from other nephrons to form collecting tubules and collecting ducts
86
2 subdivisions of nephrons
1. Cortical nephrons - in cortex
| 2. Juxtomedullary nephrons - closer to medulla, longer loops of Henle
87
Glomerulus
Site of fenestrated capillaries found in the renal corpuscles. Surrounded by Bowman's capsule, which is lined by epithelial cells on its outer surface, called parietal epithelial cells. Epithelial cells covering the surface of the glomerular capillaries are called visceral epithelial cells, or podocytes. Bowman's space is between the visceral and parietal layers.
88
Podocytes
Visceral epithelial cells, covering the surface of glomerular capillaries. They have a complex shape and a bunch of processes called foot processes or pedicels, that cover the surface of the capillaries. The pedicels are all connected by cell-cell junctions called slit diaphragms. The spaces between pedicels that these junctions cover are called filtration slits.
89
3 components of the glomerular filtration barrier
1. fenestrated epithelium
2. thick glomerular basement membrane
3. podocyte foot processes & slit diaphragms
These can be disrupted by mutations, autoimmune disorders, etc and cause loss of selective filtration functions
90
Proteinuria
Protein in the urine due to loss of selective filtration by the glomerular filtration barrier
91
Hematuria
Blood cells in the urine due to loss of selective filtration by the glomerular filtration barrier
92
What is the juxtoglomerular apparatus composed of?
Formed by 1. macula dense: columnar cell structure formed from the portion of the distal tubule located near the vascular pole of the renal corpuscles, & 2. the juxtaglomerular granular cells: adjacent smooth muscle cells of the afferent arteriole.
93
What is the role of juxtoglomerular apparatus?
Regulates glomerular blood flow in response to changes in the electrolyte concentration i the urinary filtrate by releasing renin from the JG cells.
94
Erythropoietin
A hormone produced in the peritubular capillary network, involved in the stimulation of red blood cell production in the bone marrow. It's produced in the peritubular region. Deficiency due to chronic kidney disease causes anemia.
95
3 layers of the ureters and bladder
1. Mucosa (stratified transitional epithelium/urothelium + lamina propia)
2. Muscularis - 2 (or 3 in bladder) layers of smooth muscle
3. Adventitia - loose connective tissue, serosa in upper part of bladder
96
Mucosa
stratified transitional epithelium/urothelium + lamina propia
Urothelium - includes umbrella (contain uroplakin plaques) or dome cells that contain membrane folds and vesicles used to increase cel surface area when the epithelium is distended. Performs protective functions and makes the mucosa impermeable to water.
97
3 tissue layers of the urethra
1. Mucosa - epithelial lining vaires in different regions of the urethra
2. Muscularis
3. Adventitia
98
Parts of the male urethra
1. Prostatic urethra (extends from bladder to prostate gland, lined by urothelium)
2. Membranous urethra (from prostate to penis, passes through urogenital diaphragm, lined by stratified columnar and psuedostratified epithelium)
3. Spongy or penile urethra (enclosed within erectile tissue of the penis, lined by stratified columnar, pseudo stratified columnar and stratified squamous epithelium)
4. Mucus glands of Littre - most abundant in penile urethra
99
Female urethra
Lined by the urothelium, stratified squamos, and pseudo stratified columnar epithelium
100
Proximal convoluted tubule (PCT)
Found in cortex
Functions in protein, water, electrolyte reabsorption, and secretion of anions and cations.
Made of simple cuboidal epithelium, brush border, large cells with lots of mitochondria, basal membrane folds and lateral interdigitations -- indistinct cell boundaries
101
Loop of Henle
Found in medulla and medullary rays
Functions in reabsorption of electrolytes
Made of simple squamous or simple cuboidal epithelium
102
Distal convoluted tubule
Found in the cortex
Functions in reabsorption of electrolytes
Made of simple cuboidal epithelium, smaller cells than PCT, also indistinct cell boundaries
103
Collecting tubules and ducts
Found in medulla and medullary rays
Function: Principle cells - reabsorption of water and electrolytes, Intercalated cells - regulation of acid-base balance. Its largest ducts: papillary ducts, open into the minor caulk in the perforated area cribrosa.
Made of simple cuboidal to columnar epithelium, has distinct cell boundaries
104
Kidney blood supply
```
Renal artery
Interlobular arteries
Arcuate arteries (boundary bw cortex & medull)
Interlobular arteries - travel through cortex
Afferent arterioles --> Bowman's capsule
Glomerular capillaries
Efferent arterioles--> exit BC
Peritubular capillary network or vasa recta
Interlobular veins
Arcuate veins
Interlobular
Renal vein - exits kidney
```
105
What is the kidney's response to low blood pressure?
The juxtaglomerular cells of the juxtaglomerular apparatus secrete renin, which makes angiotensin I from angiotensinogen (comes from liver). Then Angiotensin converting enzyme (from the kidney) covers Angiotensin I to Angiotensin II, which causes sodium reabsorption, vasoconstriction and aldosterone secretion.
106
Order of flow through kidney tubules
Proximal convoluted tubule (cortex) --> loop of Henle (dips down into medulla and medullary rays, which extend into cortex) --> distal convoluted tubule (cortex) --> collecting tubule and ducts (medulla and medullary rays, which extend into cortex)
