Test 1 Flashcards
circulatory system
- move blood around the body
- Delivers oxygen (O2)
- Removes carbon dioxide (CO2) and other waste products from cells
- Circulates/delivers nutrients (glucose and others) and hormones
what are the three types of the blood vessel?
Arteries:
Veins:
Capillaries:
Arteries:
blood flows AWAY from heart
Divides into smaller parts
Veins:
blood flows TOWARDS heart
Parts join and merge
Capillaries:
The microscopic exchange vessels (between arterioles and venules)
what are the three layers of blood vessel
Tunica intima
Tunica media=
Tunica externa
Tunica intima
is the innermost layer, always contains epithelium (reminder: one of the 4 tissue types) and sometimes contains elastic tissue.
-The tunica intima lines the lumen (hollow space/inside) of all blood vessels.
Tunica media (middle)
- mostly made of layers of smooth muscle tissue
- Tunica media contributes to blood pressure and blood flow; drugs, hormones, etc. can cause vasodilatation/vasoconstriction.
Tunica externa
is the outermost layer of blood vessels
- Tunica externa is primarily made of connective tissue (collagen fibers) that protects and anchors blood vessels.
Vasodilation
lumen diameter is increased (dilated)
Vasoconstriction
lumen diameter is reduced (constricted)
vasa vasorum
which nourish outer layers of the vessels. Tiny blood vessels found in the outer layer of large blood vessels like the aorta, needed to diffuse O2 and nutrients into outer layers of blood vessels
what are the three types of arteries
Elastic arteries
Muscular arteries
Arterioles
Elastic arteries
(aorta+ major branches)
Largest arteries; thick-walled
They are the nearest arteries to the heart
Contains high levels of elastic tissue (elastic tissue in all 3 tunics in elastic arteries)
Muscular arteries
Deliver blood to organs
Contain high levels of smooth muscle (thick tunica media)
Smaller and less stretchy than elastic arteries
Provide much of the body’s vasoconstriction/vasodilation
Arterioles
Smallest arteries
Arteriole diameter determines blood flow to the capillaries
what type of tunica are capillaries made of?
Capillaries are made only of tunica intima.
What are the three types of capillary?
There are three types of capillaries:
Continuous
Fenestrated (“window”)
Sinusoidal (“Curved”)
Continuous
the most common type of capillary Uninterrupted lining (no pores, endothelial cells closely attached) Found throughout the body
Fenestrated (“window”)
Oval pores in the endothelial cells allow fluids and small molecules to move through cells
Located in high absorption/filtration regions (i.e. kidney, small intestine)
Sinusoidal (“Curved”)
Large pores in the endothelial cells; large spaces and clefts between endothelial cells
Allows passage of large molecules (found in the liver, bone marrow, spleen)
Blood flows slowly through these vessels
capillary bed
interweaving networks of capilaries
vascular shunt
the central part of the capillary bed that provides the blood to the capillary bed
how many capillaries are in the average capillary bed?
10-100
Capillary sphincters
are cuffs of smooth muscle that surround the base of the capillary where it attaches to the vascular shunt.
The capillary sphincters control blood flow through capillary bed, by opening to allow increased blood flow, or contracting to shut off most of the blood flow.
two types of vein
Venules Veins
Venules
are the smallest veins
-No elastic tissue, very little muscle
Veins
- Veins (that are not venules) contain very little elastic tissue, and small to moderate amounts of muscle.
- Veins are a low-pressure environment (compared to arteries)
- Veins have thin walls and large lumens compared to arteries.
- Veins contain one-way valves that prevent blood from flowing backwards in veins.
how do veins push blood back to the heart?
The “muscular pump” that acts on veins occurs when skeletal muscles near veins contract, squeezing the vein, and pushing blood toward the heart. The unidirectional valves in veins will open to allow the blood to move towards the heart, and close before blood can backflow.
what is blood pressure?
defined at the force per unit area exerted on the wall of a vessel by its contained blood (measured as mm of Hg).
what are the three things that influence blood pressure?
Viscosity
Vessel length.
Vessel diameter.
What is the most important thing in blood pressure
Vessel diameter
Systolic Pressure
– Pressure from ventricular contraction; how much pressure your blood exerts against your artery walls when the heart beats
Diastolic Pressure
Pressure from ventricular relaxation; how much pressure your blood exerts against your artery walls while the heart is resting between beats.
What type of blood pressure is desired in capillaries?
Low, for the capillaries are extremely weak and a high blood pressure would damage them beyond compare.
distensible
How much the arteries can be stretched
Venous blood pressure
is lower than capillary blood pressure.
how are nutrients exchanged in the capilaries?
Capillaries exchange molecules is several ways: simple diffusion through epithelial cells, movement through the clefts between cells, or movement through fenestrations (pores).
hydrostatic pressure.
Fluids and molecules are pushed out of the capillaries
5 functions of tissue perfusion
1) Delivery of oxygen/nutrients to cells
2) Removal of waste from cells
3) Gas exchange in lungs
4) Absorption of nutrients from digestive tract
5) Urine formation at kidneys (fluid from the blood is filtered at kidney capillaries, this fluid becomes urine).
intrinsic blood flow regulation
Metabolic Control:
Myogenic Control:
Metabolic Control
The nutritional status of tissues regulates capillary blood flow ~ low O2 is the strongest stimulus to increase blood flow locally.
Myogenic Control
vascular smooth muscles in the tunica media will constrict or expand (vasoconstriction, vasodilation)
extrinsic blood flow regulation
Neural control
Neural control
there are special sensors in large arteries that sense pH, O2, and CO2 levels, as well as baroreceptors (sense pressure). Changes in levels of these factors signal the brain to change blood pressure (involuntary response).
medium term intrinsic
Auto regulation changes blood flow (volume per unit time) at a specific tissue without affecting the whole body blood flow, by closing or opening parts of the capillary beds (capillary sphincters).
medium term extrinsic
Hormonal control: Hormones change blood pressure through vasoconstriction, vasodilation, or blood volume.
long term intrinsic
Change in number or diameter of blood vessels (growth of new vessels through normal development, or abnormal growth of blood vessels due to tumor growth).
which part of the body controls blood volume?
The kidneys are responsible for maintaining blood volume by controlling how much urine is produced.
what two mechanisms control blood pressure in a long manner
Direct: the kidneys control urine volume. Increased blood pressure causes kidneys to lose water; decreased blood pressure leads to kidneys conserving water.
Indirect: the renin-angiotensin can be turned on in the kidneys, which causes vasoconstriction, and leads to the kidneys conserving water.
hypertension
maintained HBP
sustained systolic >140 mmHg; sustained diastolic > 90 mmHg.
leads to atherosclerosis
atherosclerosis
arteries become less compliant/ lose elasticity/become stiffer, which can cause heart attacks & stroke.
Coronary artery disease
plaques form in coronary arteries, narrowing the vessel diameter and reducing blood flow to myocardium
Circulatory shock
a condition where the blood vessels are inadequately filled, resulting in abnormal blood circulation.
Hypovolemic Shock
caused by large-scale blood loss and leads to a weak rapid pulse, intense vasoconstriction
Vascular Shock
Extreme vasodilation can be caused by anaphylaxis (allergies) and septicemia (bacteria)
Cardiogenic Shock
occurs when the heart malfunctions and blood cannot be circulated properly.
Postural Orthostatic Tachycardia Syndrome (POTS)
- characterized by lightheadedness, rapid heartbeat, low blood pressure, and sometimes fainting when the patient moves from sitting to standing (“postural”).
- When standing, blood pools away from the head due to gravity, and the heartbeat and blood pressure temporarily change to allow blood flow to return to normal levels.
- the mechanisms to return blood to the head are compromised, leading to a fast heart rate.
The diagnostic criterion is when a patient’s heartbeat increases 30 BPM within 10 minutes of standing.
-Treatments include physical therapy, increased fluids and electrolytes (lots of water and salt), medications to increase blood pressure or blood volume.
two parts of the respiratory system
upper respiratory system (from the nose to just above the larynx) and the lower respiratory system (the larynx and everything below it).
two zones of the respiratory system
divided into conducting zones (nasal cavity, pharynx, larynx, trachea, bronchus, bronchioles) and respiratory zones (lung tissues, alveoli and capillaries).
conducting zones
moves air into and out of the lungs, as well as filtering, humidifying and warming incoming air.
respiratory zones
where gas exchange occurs.
four steps in pulmonary ventilation
1) Pumping air in/out of lungs
2) External respiration, where gas exchange occurs between capillaries and alveoli in the lungs.
3) Transport of respiratory gases by blood to different parts of the body
4) Internal respiration, where gas exchange from the capillaries to the tissues of the body.
glucose equation
Glucose + O2——> CO2 + H2O + ATP (energy)
what is the respiratory tract lined with?
mucosa
mucosa
defined as one or more layers of epithelial cells and the connective tissue layer those cells lie on.
(Mucosal membranes (mucosa) line most hollow organs in the body, including the entire airway.)
what is mucosa made out of?
pseudostratified ciliated columnar epithelium
cilia
finger-like projections on the lumen side of the respiratory epithelial cells. The cilia sweep particles up and out of the airway, keeping lungs clear from dust and mucus.
Nares
(nostrils) act as airway provider; air enters into the nasal cavity via the nares.
what is the nasal cavity lined with?
Pseudostratified Ciliated Columnar Epithelium.
conchae
scroll like projections off of the nasal cavity.
-also helps regain heat and moisture associated with exhalation
meatus
a groove under the conchae that air passes through into the nasal cavity
-helps to warm humidify and filter the air.
sinus
main purpose of the sinuses is that they help the skull weigh less
sinitus
the membranes of sinuses are inflamed (swollen).
-caused by infection, or by allergies
The pharynx
(the throat)
The pharynx connects the nasal cavity to the larynx, and the oral cavity to the esophagus .
Three parts of the pharynx
nasopharynx, oropharynx, and the laryngopharynx.
tonsils
The pharynx holds the tonsils (lymphoid tissue masses that help destroy incoming pathogens)
The nasopharynx
The region of the throat just behind the nasal cavity. It is a passageway for air only. It is lined with Pseudostratified Ciliated Columnar Epithelium.
Pharyngeal tonsils
the Pharyngeal tonsils are positioned to protect the auditory tube from infection.
auditory tubes
open into the nasopharynx, which allows the middle ear equalize with atmospheric pressure
oropharynx
The oropharynx and the oral cavity are lined with Stratified Squamous Epithelium
contains the lingual (behind tongue) and palatine tonsils (on the soft palate on either side of uvula) help to protect the airway from infection.
The laryngopharynx
the portion of the throat below the oral cavity and behind the larynx.
-common passageway for both food and air, and is lined by SSE
larynx
it contains the vocal cords.
- for air only
- Pseudostratified Ciliated Columnar Epithelium.
The glottis
the vocal cords and the space between them when they are open.
The epiglottis
is a flap of flexible cartilage that covers the glottis when we swallow.
- It remains open during breathing, but will close over the airway (the glottis) to prevent food/liquids from becoming inhaled.
- The epiglottis protects the airway and lungs, and directs food into the esophagus.
The trachea
the windpipe.
a flexible tube surrounded by 15-20 C-shaped rings of hyaline cartilage.
- Pseudostratified Ciliated Columnar Epithelium
primary bronchi.
trachea split
lined by Pseudostratified Ciliated Columnar Epithelium.
bronchial tree
The parts/pathways in the bronchial tree that are found throughout the lungs are named based on their size.
what are the three parts of the bronchial tree
bronchi
bronchioles
terminal bronchioles
bronchi
Larger than 1 mm in diameter
bronchioles
0.5-1 mm is called bronchioles
terminal bronchioles
less than 0.5 mm is diameter.
bronchi size tree
Primary bronchi >secondary bronchi > tertiary bronchi >bronchioles >terminal bronchioles > respiratory bronchioles> then the structures of the alveoli begin
respiratory zone includes what d
Respiratory bronchioles alveolar duct alveolar sac alveolus
alveolar sacs
analogous to a bunch of grapes
alveoli
analogous to each grape of a bunch of grapes
- Each alveoli is covered with a network of capillaries, where the gas exchange of the blood and lungs actually occurs.
- site of gas exchange
