Exam 3 Histoo Flashcards
(354 cards)
1
Q
Classification of asthma
A
Obstructive inflammatory airway disease
2
Q
Conducting portion of the respiratory system
A
Nasal cavity, nasopharynx, larynx, trachea, bronchi, primary and terminal bronchioles.
3
Q
Structural division; extra-pulmonary segments
A
Nasal cavity, nasopharynx, larynx, trachea, primary bronchi
4
Q
Anatomical division; upper respiratory tract
A
Nasal cavity, nasopharynx, larynx
5
Q
Structural division; intrapulmonary segments
A
Secondary/lobar and tertiary/segmental bronchioles, respiratory bronchiole, alveolar duct, alveolar sac
6
Q
Anatomical division; lower respiratory tract
A
Trachea, bronchi, primary and terminal bronchioles, respiratory bronchiole, alveolar duct, alveolar sac.
7
Q
Epithelium of the upper respiratory tract
A
PSCC, simple columnar, simple cuboidal
8
Q
Epithelium in alveoli
A
Simple squamous
9
Q
Serous exocrine glands
A
Located in nasal cavity and eosinophilic stained
10
Q
Mucous exocrine glands
A
Located in the larynx, trachea, and bronchi and stain pale
11
Q
Seromucous glands
A
Located in the nasal cavity, larynx, trachea and bronchi. Stain pale and bright
12
Q
Lamina propria
A
LCT of respiratory system
13
Q
Submucosa
A
DICT
14
Q
Hyaline
A
Cartilage
15
Q
Autonomic nervous effects of respiratory system
A
Parasympathetic- bronchoconstriction and increase gland secretion
Sympathetic-bronchodilation and inhibits gland secretion
16
Q
Somatic afferent NS of respiratory system
A
Pain to parietal pleura via intercostal and phrenic nerves and Stretch visceral pleura
17
Q
Mucous membrane of respiratory system
A
The luminal epithelial lining and underlining LCT of the lamina propria
18
Q
Where are goblet cells in the respiratory tract
A
In the upper respiratory tract from the trachea to the primary bronchiole
19
Q
Where are Brush cells found
A
In the upper respiratory tract in the trachea to the primary bronchiole
20
Q
Where can granule cells and neuroendocrine cells be found in respiratory tract
A
In the upper respiratory tract from trachea to primary bronchiole
21
Q
Where can Clara cells be found
A
From the primary bronchiole, terminal bronchiole then down to the respiratory bronchiole
22
Q
Where are alveolar macrophages found
A
Alveoli
23
Q
Where are type II pneumocytes found
A
Alveoli
24
Q
What cells produce surfactant
A
Clara cells and type II pneumocytes
25
Lamina propria
LCT that contains a high number of WBC’s which contribute to the amount of lymphatic tissues and BALT
26
BALT
Plasma cells that have been activated and secrete IgA which coats the epithelial surface and provides a layer immune protection
27
Cell types in the respiratory epithelium that are not visible
Brush cells and granule cells
28
Respiratory epithelium contains
Goblet cells, ciliated cells, basal cells that are all visible. Brush and granule cells there but not visible
29
Mucociliary elevator
Goblet cells and cilia play an important and protective role in cleaning the airway. Goblet cells produce mucus that trap particulate and cilia beat moving the trapped particulate matter
30
Functions of the upper respiratory tract
Conducts air to respiratory tract, adjusts temperature/humidity of inspired air, remove dust/debris/immunoprotection, and vocalization
31
How does the epithelium in the respiratory tract change with chronic smoking or presence of toxins
Squamous Metaplasia occurs—a change from pseudostratified ciliated columnar to stratified squamous NK epithelium
32
Histological features of the trachea
PSCC and CT, smooth muscle, Seromucous and mucus glands, hyaline cartilage.
33
Histological features of primary bronchi
Respiratory epithelium and CT, incomplete ring of smooth muscle, seromucous and mucus glands, incomplete rings of of hyaline cartilage
34
What does chronic bronchitis in smokers demonstrate
Metaplasia involving an increase in the number of goblet cells relative to the number of ciliated cells. This increases mucus production but reduction of movement from cilia cells prevents mucus movement.
35
What germ layer is the epithelium of the respiratory tract from
Endoderm
36
What germ layer is the wall of the respiratory tract from
Mesoderm
37
What changes the diameter and length of the bronchi
Smooth muscle
38
Components of the intrapulmonary segment (conducting portion)
Secondary bronchi, tertiary bronchi, primary bronchioles, terminal bronchioles, respiratory bronchioles and alveoli
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What is the most distal part of the conducting system
Terminal bronchioles
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What is the most proximal part of the conducting portion
Trachea
41
Histological features of intrapulmonary segment/conducting portion (secondary bronchi and tertiary bronchi)
Respiratory epithelium, CT, may see BALT tissue, incomplete rings of smooth muscle, seromucous glands and a few mucus glands, incomplete plates of cartilage (hyaline)
42
BALT
Bronchial associated lymphatic tissue and represents aggregations of lymphocytes in the mucosa.
43
Mucosa of the primary/conducting bronchioles
Simple ciliated columnar epithelium, few goblet cells, clara cells, complete rings of smooth muscle. There is no glands and no cartilage.
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What change in airway will you see due to chronic asthma
An increase in the amount of smooth muscle in the wall of the airway
45
Acute asthma
Occurs as isolated episodes of reversible bronchial obstruction
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Chronic asthma
Is irreversible and associated with pathological changes to the wall due to inflammation
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Classifications of asthma
Extrinsic- due to allergies cause hyper-immune response
Intrinsic-typically the outcome of infections, exercise, inhalation of irritants (smoking) cause hyper responsive reaction.
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What are the three changes during an asthma attack and what are they due to
Due to hyper immune response
Excessive inflammation of mucosa and edema, smooth muscle constriction, increased glandular secretion.
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Outcome of hyper immune response due to asthma attack
Increased airway constriction and increased secretions cause partial obstruction. Although some air passes into alveoli, can’t exhale effectively making it harder to breath.
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Treatments of symptoms of asthma
Corticosteroids-decrease inflammation
Sympathetic agonist- decrease glandular secretion, causes relaxation of bronchiole muscles
51
What tissue comprising the wall of a bronchiole serves as the primary effector cell responsible for controlling airway caliber?
Smooth muscle
52
What part of the airway is maximally affected by bronchoconstriction an why?
Primary bronchi because of the complete rings of smooth muscle?
53
As a result of bronchoconstriction, the physiological outcome on airway resistance will be to:
Increase
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As a result of bronchoconstriction, what is the physiological effect on airflow and gas exchange
Airflow: decrease
Gas exchange: decrease
55
Histological appearance of terminal bronchioles
Simple ciliated cuboidal and simple cuboidal, predominately Clara cells but also brush and granule cells. Incomplete bundles of smooth muscle seen. No goblet cells, submucosa, or cartilage.
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Clara cells of terminal bronchiole
Appear as cuboidal cells with round nuclei and pale/white cytoplasm.
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Function of Clara cells
Clara (club) cells are secretory cells that produce a glycoprotein that is anti microbial, anti inflammatory and protects the bronchial epithelium form damage due to inflammation. Act as stem cells for ciliated and non ciliated epithelium
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What does the product produced by clara cells also aid in
Reduce surface tension
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Appearance of the respiratory bronchioles
Thick and thin wall segments
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Appearance of the alveolar ducts and sacs
Will have only thin walls
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Respiratory bronchioles epithelium
Simple cuboidal and simple squamous. Will have clara cells still but less in number.
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What are simple squamous epithelium lining the respiratory bronchioles called
Type I pneumocytes
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What structures do type I pneumocytes form in the gas exchange portion of the respiratory system
Form the walls of the alveolar ducts and alveoli
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What does the change in thickness from terminal bronchiole to respiratory bronchioles related to
Directly related to functional ability to exchange air in respiratory portion
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What kind of CT is seen in the respiratory bronchioles
High amounts of elastic and reticular fibers
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Why is there high amounts of elastic and reticular fibers in the respiratory bronchioles
Eslatic fibers because they are needed for recoil and to fight surface tension and reticular fibers are also type III collagen for support
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Muscular layer of the respiratory bronchioles
Can see an incomplete ring of smooth in thick sections but it will be absent in thin sections.
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What is the distal end of the respiratory bronchiole
Alveolar ducts
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Epithelium of the alveoli
Simple squamous epithelium
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Three cell types of the alveoli
Type II pneumocytes-
Type I pneumocytes -
Alveolar macrophages-
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Type II pneumocyte
Produce surfactant/act as stem cell and can give rise/renew type I or type 4
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Type I pneumocyte
air exchange and terminally differentiated. Cover 95% of surface but are fewer in number, just shaped very long.
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Alveolar macrophage
Also called dust cells. Phagocytosis of particulate matter found in the lumen of the alveoli
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CT of the alveoli
Elastic and reticular fibers only and they form the interstitial tissue of thick wall
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Alveolar wall
Inter-alveolar septum made of two parts; thick and thin sections.
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Thick inter-alveolar septum
Abundant elastic fibers and some reticular. Fibroblasts, mast cells, macrophages, and neutrophils I.e, WBC’s
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What does the inter-alveolar septum do
Provides elasticity and structural support
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Thin inter-alveolar septum
Blood air barrier and site of O2 exchange for CO2
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What is considered the interstitium in the respiratory portion of the intrapulmonary segment
Interalveolar septum
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Alveolar pores
Equalize pressure and allow collateral air flow if alveoli is blocked
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What interrupts the septal wall and connects adjacent alveoli
Alveolar pores
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What makes the blood air barrier in the alveoli
Type I pneumocyte, BM, endothelial cells that line a capillary. (Thin portion of alveolar septum)
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Elastic recoil is _____________ proportional to compliance
Inversely
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If compliance increases what happens to elastic recoil
It decreases
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Elastance
Also elastic recoil and its a measure of the tendency of a hollow organ to recoil toward its original dimension upon removal of a distending or compressing force
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What determines the elasticity and ability of a hollow organ to recoil
Amount of elastic fibers in the wall of the hollow organ
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What prevents the ability of a hollow organ to expand
High surface tension
88
Compliance
Compliance is the ability of a hollow organ to distend/increase volume but resist recoil toward its original dimensions on application of a distending or compressing force
89
What effects a larger airway to expand and then resist recoil
Wall thickness, amount smooth muscle and collagen and type of collagen, and amount of surface tension at the air water interface.
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What affects compliance in the alveoli
The amount of elasticity and amount of surface tension
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Emphysema is hallmarked by what
The destruction of the alveolar wall
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In emphysema neutrophils and macrophages secrete an elastase enzyme that..
Destroys the elastic fibers and leads to a loss of elasticity and recoil
93
What does destruction of the alveolar wall cause
A decrease in alveolar surface tension and less gas exchange.
94
What will be the impact of decreased elastic fibers on the
elasticity and compliance be
Decrease elastance and increase compliance
95
Pulmonary fibrosis
Is characterized by an increase in interseptal wall thickness due to increased collagen fiber deposit
96
What will be the impact of increased wall thickness and
collagen on compliance in pulmonary fibrosis
Decrease compliance
97
What germ layer is the hart derived from
Mesoderm
98
Lymphatic vascular system
Collects excess interstitial fluid from the tissue spaces as lymph and return it to the blood
99
What is lymph
Protein rich filtrate of plasma that contains wasate, antigens, cellular debris and lymphocytes
100
What does lymph filter through before it enters the cardiovascular system
Lymph nodes
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What transports lymphocytes from CT to other regions
Lymph circulates lymphocytes
102
How does lymph enter the venous system
The thoracic duct
103
Cardiovascular system
Includes heart that pumps blood to and form lungs and body organs
104
Pulmonary circulation
Deoxygenated blood from right side of heart—>pulmonary artery—>lungs—>oxygenated blood carried by pulmonary veins—>left side of heart for distribution
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Which pulmonary vessels carry deoxygenated blood
Pulmonary arteries
106
Which pulmonary vessels carry oxygenated blood
Pulmonary veins
107
Systemic circulation
Left ventricle—>aorta—>arterial distribution to body tissues—>capillary in tissues—>venous collecting system transports deoxygenated blood—>right atrium of heart
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Portal circulation
Supplementary venous system in which two capillary beds are connected by a vein prior to heart
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Hepatic portal
GI capillary—>distributing vein—>liver capillary—>systemic vein—>heart
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Hypophyseal portal
Hypothalamus capillary—>distributing vein—>pituitary capillary—>systemic circulation
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Vessels that function in blood distribution and collection
Elastic arteries, muscular arteries, medium veins
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Vessels that function in interchange of metabolites between blood vessels and CT
Arterioles, capillaries, venules
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Path of blood through vessels
Elastic arteries—>muscular arteries—>arterioles—>capillaries—>postcapillary venule—>venule—>medium vein—>large vein
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Blood pressure in the arterial system
100-40 mmHg
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What are the distributing vessels
Muscular arteries
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Arteriovenous anastomsis
Channels with direct connection from arteriole to venule that bypass a capillary bed to conserve heat
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Precapillary sphincter of arteriole
Smooth muscle that acts as a precapillary sphincter to regulate blood to capillary bed and determines if it by passes capillary via a shunt
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Three concentric layers surrounding the lumen of a hollow tube
Tunica intima, tunica media, tunica adventitia
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What is common to all parts of the circulatory system and is necessary to maintain blood vessel function
Endothelium (simple squamous epithelium)
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Tunica intima
Internal layer of endothelium BM, LCT
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Tunica media
Middle layer of mainly smooth muscle and some elastic fibers and type III collagen fibers. Contains fibers of the ANS.
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Tunica adventitia
Outer layer of DICT—>LCT that connects the vessel to surrounding structures, contains fibers of ANS
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What lines the lumen of all blood, lymphatic systems and heart
Endothelium
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What vessels contain only endothelium with complete or incomplete basement membranes
Capillaries
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Variation in each tunica exists for different vessels T/F
True
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Arrangement of sub layers from the lumen out in the tunica intima
Endothelium, BM, subendothelial CT, internal elastic lamina (in muscular arteries)
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Arrangement of sub layers from the lumen out in the tunica media
Muscular layer, ECM CT fibers, external elastic Lamina or elastic sheet
128
Components of the tunica intima
Simple squamous epithelium, ECM, LCT, aggregation of elastic fibers
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Components of tunica media
Smooth muscle, smooth muscle cells arranged helically with intervening CT fibers, large aggregation of elastic fibers arranged as sheets throughout media or bundles between media and externa
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Components of tunica adventitia
DICT—>LCT, nerve fascicles (ANS), blood vessels, smooth muscle in wall of large veins arranged longitudinally
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Function of tunica intima
Diffusion barrier between blood and vessel wall, selectively permeability, coagulation via clotting proteins secreted from endothelium, controls adhesion of WBC/allows passage from vessel, accommodates volume fluctuation through the vessel
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Function of tunica media
Regulates luminal diameter and determines vascular resistance, produce ECM fibers, vessel elasticity and recoil distribution of fibers varies based on vessel size
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Function of the tunica adventitia
Attaches vessel to neighboring structures
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What supplies nutrients to the walls of larger vessels
Vasa vasorum
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What supplies ANS innervation to large vessels
Nervi vasorum
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What are arteries characterized by
Size and characteristics of tunica media
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What is the thickest layer of elastic/conducting vessels
Tunica media
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Tunica intima of elastic/conducting vessels
Well developed with endothelium and subendothelium CT
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Tunica adventitia of elastic/conducting vessels
Is much thinner than the media and contains numerous lymphatic vessels, vasa vasorum and Nervi vasorum
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What is the functional significance of elastin
Allows elastic arteries to stretch when large volumes of blood are ejected at ventricular systole
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What helps propel the blood forward in diastole
Elastic energy
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Where is the internal elastic lamina
Between tunica intima and tunica media
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Where is the external elastic lamina
Between tunica media and tunica adventitia
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What vessels is the EEL more prominent in
Muscular artery. It is inconspicuous in elastic arteries due to the abundance of elastic fibers present
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What is the thickest layer in muscular/distributing arteries
Tunica media
146
Tunica media of muscular/distributing arteries
Contains abundant smooth muscle cells, EEL located between smooth muscle and TA
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Tunica adventitia of muscular/distributing arteries
Consists of DICT to LCT, contains lymphatic vessels in larger vessels, vasa vasorum, Nervi vasorum, all of which may penetrate to the outer part of the media
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Atherosclerosis
Is an inflammatory disease that affects the tunica intima of the large elastic and muscular arteries. Characterized by endothelial damage, inflammation, increased synthesis of collagen fibers, and decreased production of elastic fibers
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Atheroma
Fibro fatty plaque formation
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Atheromas in elastic arteries
Produce localized destruction within the wall, weakening it and causing the arterial wall to bulge which can rupture
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Atheromas is muscular arteries
Cause narrowing of the lumen and occlusion to vessels which can lead to ischemia and hypoxia
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Arteriosclerosis
Is a broader term for narrowing or hardening of the smaller arteries due to age related loss of elasticity
153
Thrombus
Is a blood clot inside a vessel (stationary)
154
What represents the transition to micro vasculature
Arterioles
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Arterials do not have the same three layers as larger vessels (T/F)
False. They do have the same three layers they are just greatly diminished
156
Tunica intima of arterioles
Is very thin, single layer of squamous epithelium, thin layer of CT, IEL is thin to absent
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Tunica media of arterioles
Consists of 1-6 layers of circularly arranged in smooth muscle layers. EEL is absent
158
Tunica adventitia of arterioles
Is thin and inconspicuous, merges in with the surrounding CT tissue
159
How do primary resistance vessels enter an organ to distribute and control blood flow into capillary beds
They enter an organ to distribute and control blood flow by contacting or dilating the size of the lumen
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What vessels are considered part of the resistance vasculature that provides the majority of the resistance to blood flow in the body
Arterioles
161
What is the importance of arterioles
They will be the primary site of both resistance and regulation of blood pressure
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Terminal arteriole
Arteriole closest to capillary bed
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Precapillary sphincters
Are incomplete ring of smooth muscles at terminal end of arteriole/beginning of capillary
164
What is there function of a terminal arteriole
Regulate the flow of blood to specific capillary beds
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AV shunt
Arteriole connects directly with venule and allows blood to bypass a capillary bed, conserve heat, and is localized/specialized routes for blood in skin, lips, erectile tissue.
166
What is a key feature of an AV shunt
AV sphincters
167
AV sphincters
Contraction or relaxation of incomplete rings of smooth muscle at terminal end of arteriole end of AV shunt determine blood flow
168
What is the function of the AV shunt
AV shunts directly connect the arterial and venous systems and allow blood to temporarily bypass capillaries.
169
What structure helps in thermoregulation in the skin by routing blood
AV shunts
170
Composition of capillaries
Single layer of flattened endothelial cells with a variable basement membrane. There are no muscular or adventitia layers.
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Capillaries create ____________
Large surface area for exchange
172
Function of capillaries
To perfuse tissue, exchange of gases and other substnaces occurs in capillaries between the blood and the surrounding cells and their tissue fluid
173
Ranges of capillary lumen
5-10 micrometers
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What is the flow through capillaries described as
Microcirculation
175
What optimizes capillaries for the exchange of nutrients and wastes between blood and tissues
Thin walls, extensive surface area, and slow, pulsation blood flow
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Continuous capillary
Continuous endothelial lining with tight junctions between their endothelial cells along with intercellular clefts through which small molecules like ions can pass through and produce minimal fluid leakage
177
Functions of continuous capillaries
Selective exchange- all molecules across the endothelium must cross the cells by diffusion or transcytosis
178
What is the most common type of capillary found in all major organs of the body
Continuous capillaries
179
Where are continuous capillaries located
Brain, respiratory, heart, skin, digestive tract
180
Fenestrated capillaries
BM, tight junctions, but also fenestrations through the endothelial cells that allows for greater exchange across the endothelium.
181
Functions of Fenestrated capillaries
Exchange of macromolecules thus found in organs where molecular exchange with the blood is important.
182
Discontinuous or sinusoidal capillaries
Wider diameter than the other types and have discontinuities between the endothelial cells, large fenestrations through the cells, and a partial discontinuous basement membrane
183
Where can you find Fenestrated capillaries
Small intestine, kidneys/glomerulus, choroid plexus of the brain and most endocrine organs, pancreas, hypthalamus, pituitary, pineal, and thyroid gland
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Function of discontinuous capillaries
Exchange of macromolecules and passage of cells
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Where do you find discontinuous capillaries
Bone marrow, liver, and spleen
186
What does vasodilation of an arteriole result in
Increased perfusion and increased pressure of capillary bed which increases the fluid passing from capillary to CT
187
What does vasoconstriction of an arteriole result in
Decreased perfusion and decreased pressure of the capillary bed. So increases uptake/absorption of excess fluid from CT back into venous system
188
What affects the flow rate
Local hormones, and/or neurotransmitters from ANS cause vasodilation and vasoconstriction of arterioles and arteries which will impact capillary perfusion
189
Where is hydrostatic pressure high vs low
High on arteriole side and low on venule side
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Where is osmotic pressure low vs high
Low on arteriole side and high on venule side
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What reabsorbs excess interstitial/CT fluid
Venous end of circulation
192
Where does fluid leave vessels and enter CT
Arteriole end of circulation
193
What determines the total surface area available for exchange
Density of capillary network
194
If a tissue has a high metabolic need what happens to the capillary density
It tends to be high as well
195
What is the function of a metarteriole
Controls whether blood flows through the capillary bed or bypasses it via an AV shunt. Important during stress, exertion, and temp control
196
Postcapillary venule
Receives blood directly from the capillary bed and is found in all CT
197
What characteristics make the postcapillary venules favorable for fluid and solute exchange
Slow flow; provide favorable conditions for passive diffusion between blood and interstitial fluid
More permeable to solutes than arterioles
198
Endothelial cells of postcapillary venules can alter their…
permeability to fluid and solutes in response to physiological and inflammatory stimuli
199
What is the primary site of a white blood cell to adhere to the endothelium and leave the circulation at site of infection or tissue damage
Postcapillary venules
200
What are some key histological features of a postcapillary venule
TI layer is inconspicuous, TM with one or two muscle fiber layers, lacks valves, TA merges with surrounding tissue
201
What do small to medium sized veins do
Receive blood from collecting and small veins
202
A _______________ is a collecting venule
Postcapillary venule
203
What do veins tend to run parallel with
Corresponding muscular artery
204
Veins are more numerous than arteries of similar size T/F
True
205
Key histological features of small to medium veins
Collapsed lumen with RBC’s, TI has one way valves, TM is smooth muscle to prevent pooling, lack external or internal elastic layer, TA IS THICKER THAN TM
206
One way valves
In folding of TI visible in the lumen of veins to help direct blood flow
207
Where are one way valves more common
In the veins of the lower extremities to prevent back flow
208
Large veins are classified as what and why
As capacitance vessels due to high volumes of blood contained and the ability to readily accommodate changes in the blood volume.
209
Key histological features of large veins
Well developed TA, smooth muscle in TM, smooth muscle may also be seen in TA to aid in propelling blood back to heart, muscle of TA is arranged longitudinally, valves present in leg veins but absent in vena cava and portal vein
210
What contributes to venous return to the right atrium
Calf muscle pump, vein valves, respiration
211
Calf muscle pump
External compression and action of the calf skeletal muscle helps force blood upward
212
Vein valves
Healthy valves close, preventing blood from refluxing of pooling during relaxation. Smooth muscle longitudinally arranged in TA of vessels
213
Respiration contribution to venous return
The movement of the diaphragm during inspiration creates a negative intrathoracic pressure that assists the return of blood from the legs and abdomen to the right side of the heart
214
What causes varicose veins
Failure of valves to close
215
What does a high endothelial venule or specialized post capillary venule do
Allows selective passage of lymphocytes in to lymph node and MALT
216
TI and TM of high endothelial venule/specialized post capillary venule
Cuboidal (endothelium), TM has some CT but no Smooth muscle
217
Functions of the integument
Renewable, resists abrasion, protects against infection, protective barrier against UV light, prevents desiccation and absorption, thermoregulation, excretory organ, endocrine function, somatic sensory perception, wound healing.
218
What are the two categories of skin
Thick and thin
219
Thick skin
Also called glabrous/smooth hairless. Found on palms of hands, soles of feet.
220
Thin hair
Most of the body and scalp also hairy
221
Structures of the skin that are ectoderm derived
Epidermis, glands, hair follicles, nails
222
What germ layer forms the dermis
Mesoderm
223
What makes up the dermis
DICT and LCT
224
What germ layer is the hypodermis derived from
Mesoderm
225
What makes up the hypodermis
Adipose
226
What is the external outside surface of the integument
Cutaneous membrane
227
What is the order of the underlying layers of CT from superficial to deep
LCT, DICT, adipose/LCT
228
Type of tissue in the epidermis
SSK
229
Features of epidermis
4-5 layers of epithelium with the superficial layer being keratinized, avascular, varying thickness of SSK, contains nails, sensory receptors, ducts of glands and hair follicles pass through
230
Two layers of the dermis
Papillary (LCT) and reticular (DICT)
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What layer makes up the bulk of the dermis
Reticular layer
232
What cells are contained in the dermis
WBC, macrophages, mast cells, plasma cells
233
What vessels are contained in the dermis
Blood vessels, arterio-venous anastomoses, capillaries
234
What neuronal structures reside in the dermis
Nerve fibers, sensory receptors,
235
What structures are in the dermis
Hair follicles, sebaceous glands, smooth muscle, ducts
236
What forms a pill sebaceous unit
Hair follicle, smooth muscle, and sebaceous (oil) glands
237
Anatomical name of the hypodermis
Superficial fascia/subcutaneous tissue
238
What is contained in the hypodermis
Subcutaneous LCT tissue layer and adipose, contained larger blood vessels, some secretory parts of glands, base of hair follicles, sensory receptors, WBC, macrophages, mast cells, plasma cells
239
What is the most variable layer between thick and thin skin
Superficial layer called stratum corneum
240
What histological appearance does the stratum corneum have in thick and thin skin
It’s anucleated and comprised of layers of keratin proteins and phospholipids
241
What layer contains stem cells and progenitor cells that will mature into keratinocytes
Stratum basale
242
What layer contains intensely basophilic stained granules in both thin and thick skin
Stratum granulosum
243
What structures contain stem cells
Sebaceous glands, sweat glands, and hair follicles
244
Stratum basale
Single layer of cuboidal shaped cells, keratinocytes appear basophillic due to size and round shaped nuclei. This layer serves as stem cell source.
245
Epithelial stem cell layer
Rapidly renewing layer that provides continual turnover. SB can self renew or become a mitotically active progenitor cell.
246
What cells migrate to the surface and become flattened and synthesized keratin
Progenitor keratinocytes
247
Hemidesmosomes
Attach the stratum basale to the basement membrane, the BM attaches epithelium to the dermis
248
Desmosomes
Attach adjacent cells together and are found in all layers throughout the epidermis
249
Stratum spinosum
Has several layers (5-7), adjacent cells are attached at spines by desmosomes, mitotically active cells
250
How are the keratinocytes characterized in the stratum spinosum
By cytoplasmic extensions extending between cells (desmosomes)
251
Stratum granulosum
1-3 layers thick and functions to synthesize a protein that causes the individual keratin filaments to aggregate into bundles of keratin. Also synthesizes phospholipids that spread between the keratin filaments in the stratum corneum to form a water barrier
252
Where is the protein created in the stratum granulosum stored
In basophilic granules called keratohyalin granules
253
Key histological feature of stratum granulosum
Keratohyalin granules
254
Stratum lucidum
Unique to thick skin! Found at the interface of the granulosum and corneum, blue refractile appearnce, keratinocyte cells dont have a nucleus—undergoing apoptosis
255
Stratum corneum
Most superficial layer comprised of keratin bundles and apoptotic keratinocytes. No organelles present just anucleated squamous cells.
256
What forms the water barrier and aids in preventing desiccation in the stratum corneum
Combination of phospholipids found between the keratin filaments provide a water barrier between granulosum and corneum.
257
The stratum corneum does not vary in thickness with thick and thin skin T/F
False. It varies greatly from 5-7 layers to 15-20.
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Keratinocyte
Predominant cell type found throughout all layers of epithelium. They synthesize and assemble the proteins involved in keratinization. Resists abrasion and produces phospholipids to form water barrier
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What germ layer do keratinocytes come from
Ectoderm
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Melanocyte
Scattered cells found in stratum basale, synthesizes melanin, protects against UV radiation (increased exposure+increased synthesis).
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How do melanocytes transfer melanin pigment
In vesicles to groups of progenitor keratinocytes in stratum basale.
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How does melanocyte vary between races
They do not vary much at all but the rate of vesicular transfer, melanin storage, breakdown of pigment is what changes.
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What does a slower breakdown of melanin result in
Wider distribution of melanin throughout layers
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What are other factors that affect melanin
Type and ratio of pigments synthesized vary and distribution of melanocytes within different parts of the body
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What leads to albinism
Faulty melanin synthesis due defects in enzymatic pathway that forms melanin
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What is melanoma
An aggressive highly malignant skin cancer arising from melanocytes.
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Langerhans cells
Are found in upper layer of stratum spinosum and are a type of phagocytic WBC. They function as an antigen presenting cell they phagocytose antigen and present it to T cells in the lymph node.
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Clinical implications of langerhans cells
Involved in delayed hypersensitivity reactions
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What germ layer do langerhans cells come form
Mesoderm
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Merkel cells
Modified keratinocytes found in the stratum basale and function to form sensory receptor that detects cutaneous sensation by responding to mechanical deflection.
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What does a merkel cell complex with
Myelinated sensory nerve fiber to form a sensory receptor called a mechanoreceptor
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What do merkel cells represent
A modified sensory receptor that complexes with an afferent sensory nerve fiber
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Dermal epidermal junction
Interdigitaitng between s basale cell layer of epidermis/basement membrane and the LCT layer dermis
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What does the dermal epidermal junction function to do
To minimize friction. They are higher in number and deeper interdigitation in thick skin
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What skin exhibits the deepest ridges
Skin that is subject to higher amounts of friction
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What are the structures at the dermal-epidermal junction
Dermal papillae and epidermal ridges
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Dermal papillae
Upward projection of dermis into epidermis
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Epidermal ridge
Downward projections of epidermis into dermis
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Papillary layer of dermis
Thin superficial layer of LCT that forms dermal papillae
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Structures in the papillary layer
Superficial capillary network, meissner’s corpuscle, merkels disc
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Superficial capillary network
Important for temperature control and free nerve endings
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Meissner’s corpuscle
Cutaneous nerve endings located in the dermal papilla that detects touch
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Merkel’s disc
Name for the myelinated afferent nerve fiber that complexes with merkel cell
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Reticular layer
Thick layer of DICT
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Structures in reticular layer
Small blood vessels, arterio-venous anastomosis (AV shunts), hair follicles, sebaceous glands, ducts of sweat glands, pacinian corpuscles, ruffini nerve endings
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Hypodermis/subcutaneous superficial fascia
Loose CT and adipose tissue, dermal-hypodermal junction
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What structures are contained in the dermal-hypodermal junction
Contains secretory cells for sweat glands, pacinian corpuscles, small arteries, veins, and base of hair follicle may extend into deeper hypodermis.
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What allows the skin to serve in heat exchange for thermoregulation
It’s large surface area and extensive vascularization
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What NS regulates/controls the cutaneous temperature
Sympathetic
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What does the sympathetic activity control
Arterial blood flow to capillary beds via arteriole vasoconstriction and dilation. Opening and closing of AV shunts.
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Where’s re AV shunts mainly found
Thick skin, lips, ears and nose
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What does an increased body temp result in
Promotes vasodilation of superficial capillary beds
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How does the the increased body temp cause vasodilation
Precapillary sphincters relax/open and AV shunts close/constricts
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What does the vasodilation result in with an increased body temp
Opening of capillary beds diverts blood flow to superficial capillaries to dissipate heat. The sympathetic NS also stimulates sweat glands to aid in cooling.
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What does a cold body temp promote
Vasoconstriction/ closure of superficial capillary beds to conserve heat
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What mechanism occurs with a decrease body temp and vasoconstriction
Precapillary sphincters close/constrict and AV shunts open
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What is the outcome of vasodilation in a decrease body temp
Closure of superficial capillary beds diverts blood to AV anastomoses and AV shunts blood directly form arteriole to venule and keeps blood deeper in body tissue
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Epidermal skin appendages
Pilosebaceous unit
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Where are hair follicles found
In hypodermis/reticular dermis and extends through the dermis to epidermis
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What is hair
Layers of keratinized cells
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What are key histological features of hair follicles
Shaft of follicle is associated with sebaceous glands, aporcrine sweat glands, arrector pili muscles
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What germ layer are hair follicles from
Ectoderm
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Arrector pili muscles
Smooth muscle, located in the reticular layer of the dermis and attaches to the outer shaft of hair follicles and adjacent to sebaceous glands.
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What germ layer do arrector pili muscles come from
Mesoderm
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Sebaceous gland
Is an exocrine gland located in the reticular dermis/hypodermis and are under hormonal control form puberty on.
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What method of secretion do sebaceous glands use
Holocrine method
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What oily substance does a sebaceous gland produce
Sebum
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What germ layer are sebaceous glands developed from
Ectoderm
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What are the sweat glands of the skin
Exocrine glands
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What are the sweat glands of the skin innervated by
Sympathetic NS
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What method of secretion do the sweat glands of the skin use
Merocrine
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Apocrine sweat glands
Have secretory units found in the reticular layer of dermis/hypodermis junction and ducts that extend through dermis and open to hair follicles
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Where are apocrine sweat glands found
In the skin of the axilla and external genitalia
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What do apocrine sweat glands respond to and produce
Emotional stressors and produce a protein based product that can produce an odor upon interacting with bacteria on the skin
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Eccrine sweat glands
Secretory units found in the reticular layer of the dermis/hypodermis with ducts that extend through the dermis and open onto the external surface of the epidermis
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Where are eccrine sweat glands located
All over the body except in the lips and external genitalia
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Where are there high numbers of eccrine glands
Forehead, palms/soles of feet, axilla
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What is the function of eccrine glands and what do they produce
Mainly regulate temperature but can respond to emotional stressors. They produce a watery/electrolyte product
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What are the functional classifications of cutaneous sensory receptors
Mechanoreceptor, thermoreceptors, nociceptors
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Mechanoreceptor
Sense mechanical displacement and it is perceived as light discriminative touch, pressure, vibration, stretch and tension
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Thermoreceptors
Sense temperature change and it is perceived as warm or cool depending on the receptor
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Nociceptors
Sense extreme stimuli of temp, mechanical, and chemical stimuli. These sensations are perceived as pain; either fast and sharp (1st pain and unmyelinated) or slow and dull (2nd and unmyelinated)
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Motor innervation of the integument is controlled by what
Autonomic NS—sympathetic
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Where do all ANS sympathetic postganglionic fibers terminate
In the dermis on smooth muscle of blood vessels, arrector pili muscles, sweat glands
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What classification of receptors do apocrine and eccrine sweat glands utilize
Apocrine- adrenergic
Eccrine-cholinergic
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What are the structural classifications of sensory receptors
Non-encapsulated/ free and encapsulated/CT and myelin covering
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What is the functional significance of encapsulated receptors
Encapsulation increases specificity of nerve impulse transmission
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Functional significance of myelinated vs unmyelinated receptors
Myelination increases conduction speed
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Types of non-encapsulated/free nerve ending receptors
Free nerve ending receptors, specialized free receptor, hair follicle receptor
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Free nerve endings
Nociceptors, thermoreceptors, mechanoreceptors
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Specialized free receptors
Merkel corpuscle which are mechanoreceptors that detect light touch.
Hair follicle receptor which are also mechanoreceptors and detect deformation of hair so if it’s upright or laying down
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What are the four types of encapsulated mechanoreceptors
Meissner’s corpuscle, Krause end bulbs, pacinian corpuscles, ruffini corpuscle
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Meissner’s corpuscle
Located in dermal papillae of papillary layer in thick skin and they detect light discriminative touch
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Krause end bulbs
Located in papillary layer of dermis of thick skin and function in cold thermal/pressure detection
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Pacinian corpuscle
Located in reticular layer of dermis/hypodermis of all skin and some organs and function in transient deep pressure/vibration.
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Ruffini corpuscle
Located in reticular layer of dermis/hypodermis of skin and function to detect stretching of CT fibers/pressure joints
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What kind of epithelial membrane is the skin
A cutaneous membrane covering the external surface of the body
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What kind of epithelial membrane is the oral mucosa
Is a mucous membrane that lines the interior lumen of a hollow organ or lines a passageway that leads to the outside surface
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What is the skin turn over time and what skin does it take longer in
28-55 days and thick skin takes longer
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What is the oral mucosa turnover time
14-20 days
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Epithelium of the oral mucosa
SSK, SSPK, SSNK
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SSPK
Has no stratum corneum only SG, SS, SB
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What types of intracellular and cell-extracellular junctions exist in the oral cavity
Desmosomes and hemidesmosomes
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Intraepithelial separation
Affects desmosomes
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Subepithelial separation
Affects hemidesmosomes
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Do both skin and oral mucosa exhibit rete ridges and dermal papillae
Yes
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What is the name of the LCT layer in the oral mucosa
Papillary layer of lamina propria
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Name of DICT layer of oral mucosa
Reticular layer of lamina propria
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Name of CT and adipose layer of oral mucosa
Submucosa but it is not present in all regions of the oral mucosa
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How do skin and oral mucosa differ in healing
Oral mucosa very rarely forms scar tissue because it exhibits faster rate of epithelial renewal
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What are factors influencing healing in OM
1) Local environment of oral cavity = moist,
ambient temp
2) Presence of saliva and salivary proteins
3) Reduced inflammation
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What helps reduced inflammation in the OM
Rate of epithelial turnover
Type of fibroblasts and rate of cell turnover impacts ECM synthesis decreases scar formation
Fewer inflammatory cells
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What are complicated wounds in the OM that may scar
Tooth extraction and pulp inflammation
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Is angiogenesis decreased in wound healing of the skin or oral mucosa
Oral mucosa
