Human Anatomy CH 20 Flashcards
What are the 5 types of blood vessels? Describe each one briefly. Which ones are the major ones?
- Arteries (M)- Carry blood away from the heart
- Arterioles - Smallest arteries
- Capillaries (M) - Smallest blood vessels
- Venules - Smallest veins that receive blood from the capillaries
- Veins (M) - Receive blood from venules
What are the 3 layers (tunics) of a blood vessel? What do they contain and what are their functions?
- Tunica Intima - Contains endothelium (simple squamous epithelium) and subendothelial layer. Vessels are larger than 1mm
- Tunica Media - Sheets of smooth muscle that cause vasoconstriction and vasodilation
- Tunica Externa - Composed of connective tissue
What is the central blood-filled space of a vessel called?
Lumen
What’s another word for vasoconstriction and vasodilation?
Vasoconstriction - Contraction
Vasodilation - Relaxation
What are the largest arteries? What is its’ diameter range?
Elastic arteries - 2.5 cm to 1 cm
What is an alternative name for elastic arteries? What does it include?
Conducting arteries; includes aorta and major branches
What does the high elastin in elastic arteries do?
Dampens surge of blood pressure
Where do the muscular (distributing) arteries lie? What is its’ diameter range? What arteries fall under this category?
- Lie distal to elastic arteries
- 1 cm to 0.3 mm
- Most named arteries
What are some unique physical features of the Muscular (distributing) arteries?
Tunica media is thick, has external and internal elastic laminae
What is the diameter range of arterioles?
0.3 mm to 10 um
Do larger arterioles possess all 3 tunics?
Yes
What controls the diameters of arterioles?
Local factors in the tissues and the sympathetic nervous system
What are the smallest blood vessels? What is the diameter range for them?
Capillaries; 8 to 10 um
How do red blood cells pass through capillaries?
Single file
What are the 4 site specific functions of capillaries?
- Lungs - oxygen enters blood, carbon dioxide leaves
- Small intestines - receive digested nutrients
- Endocrine glands - pick up hormones
- Kidneys - removal of nitrogenous wastes
What is the most common type of capillary? Where does it occur?
Continuous capillaries; occur in most organs
What joins epithelial cells in continuous capillaries?
Tight junctions and desmosomes
What are intercellular clefts? What is their function?
Gaps of unjoined membranes that allow small molecules in and out of capillaries
In fenestrated capillaries, what are joined together? What do they have in their endothelium?
Tight junctions and desmosomes; have pores in endothelium
Where are fenestrated capillaries mostly found/occur (name 3)?
- Intestines
- Glomeruli of kidneys
- Endocrine glands
What are sinusoids? What type of capillary is it? What are its intercellular clefts like?
Wide, leaky, fenestrated capillaries with intercellular clefts that are wide open found in some organs
Where do sinusoids occur? What are their physical characteristics?
Bone marrow and spleen; have a large diameter and twisted course
What are the 4 routes in and out of capillaries?
- Direct diffusion
- Through intercellular clefts
- Through cytoplasmic vesicles
- Through fenestrations
What type of capillary makes up the blood brain barrier?
Low-permeability capillaries
Describe the capillary in the blood brain barrier. What are its intercellular clefts like?
Capillaries have tight junctions and no intercellular clefts are present
What does is the blood brain barrier NOT a barrier against?
Oxygen, CO2, and some anesthetics
Vital molecules pass through the blood brain barrier due to _________________
Highly selective transport mechanism
What are capillary beds?
Network of capillaries running through tissues
What regulates the flow of blood to tissues?
Precapillary spinchters
Tendons and ligaments are _______________
poorly vascularized
Epithelia and cartilage are ________________. Instead they, __________________
avascular; receive nutrients from nearby connective tissue
What are the functions of venous vessels?
Conducts blood from capillaries toward the heart
Blood pressure in venous vessels are ____________ than arteries
much lower
What is the diameter range for venules?
8 to 100 um
What are the smallest venules called?
Postcapillary venules
What percentage of blood is in the veins at any given time?
65%
What are the 4 structural differences between veins and arteries?
- Lumens are larger
- Tunica externa is thicker
- Less elastin in walls
- Walls are thinner
What are 2 mechanisms that counteract low venous pressure?
- Valves
- Skeletal muscle pump
What do valves do?
Prevent the backflow of blood
In which veins, are valves NOT present?
Veins of thoracic and abdominal cavities
How does the skeletal muscle pump work?
Muscles press against thin-walled veins
What do vessels interconnect to form?
Vascular anastomoses
Veins _________ more frequently than arteries
anastomose
What do neighboring arteries form? What do they provide?
Arterial anastomoses; provide collateral channels
Organs _________ blood from ______ than __________
receive; more; one arterial source
Where does the pulmonary trunk leave? What does it divide into?
Right ventricle; divides into right and left pulmonary arteries
What do the superior and inferior pulmonary veins do?
Carry oxygenated blood into the left atrium
_____________ have thinner walls than _____________
Vessels of pulmonary circuit; systemic vessels
_____________ is lower in _________________
Maximum arterial pressure; pulmonary circuit
What do systemic arteries do?
Carry oxygenated blood away from the heart
What is the largest artery in the body?
Aorta
Where does the ascending aorta arise from? What does it branch into?
Left ventricle; branches into coronary arteries
What artery lies posterior to the manubrium? What does it branch into?
Aortic arch
Branches into: Brachiocephalic trunk, left common carotid, left subclavian arteries
What continues from the aortic arch?
Descending aorta
What vertebrae regions does the thoracic aorta lie in?
T5-T12
What does the abdominal aorta divide into?
Right and left common iliac arteries
What vertebrae regions does the abdominal aorta end at?
L4
What are the pairs of arteries that supply to the head and neck?
Carotid and subclavian arteries
What do the subclavian arteries branch into? List all 3
- Vertebral arteries
- Thyrocervical trunk
- Costocervical trunk
What is located in the anterior triangle of the neck?
Common carotid artery
What are the 2 branches of the common carotid artery?
External and internal carotid arteries
The external carotid artery branches into what 7 arteries?
- Superior thyroid artery
- Lingual artery
- Facial artery
- Occipital artery
- Posterior auricular artery
- Superficial temporal artery
- Maxillary artery
The internal carotid artery branches into what 4 arteries?
- Ophthalamic artery
- Anterior cerebral artery
- Anterior communicating artery
- Middle cerebral artery
What does the anterior communicating artery form?
Forms part of the cerebral arterial circle
Where do the right and left subclavian arteries originate/arise from respectively?
- Originates from brachiocephalic trunk
- Arises as third branch from aortic arch
What do the vertebral arteries do? What do they join to form?
Supply posterior brain; forms basilar artery
What does the Basilar artery divide into?
2 posterior cerebral arteries
What do the posterior communicating arteries connect together?
Posterior cerebral arteries to middle cerebral arteries
Where does the thyrocervical trunk sends it branches (and how many)?
2 branches posteriorly over scapulae
1 branch anteriorly to the inferior part of the thyroid gland
Where does the costocervical trunk send its branches?
1 branch superiorly to deep muscles of the neck
1 branch inferiorly to intercostal spaces
What supplies the anterior thoracic walls?
Internal thoracic arteries
What are the branches of the internal thoracic arteries called?
Anterior intercostal arteries
What arteries are the inferior nine pairs that arise from thoracic aorta?
Posterior intercostal arteries
The __________ artery enters the __________ as the ______________ artery
subclavian; axilla; axillary
What does the axillary artery become? Where does it become it?
Becomes: Brachial artery at inferior border of teres major
What does the brachial artery divide into?
Radial and ulnar artery
List the 8 arteries of the abdominal aorta
- Inferior phrenic arteries
- Celiac trunk
- Superior mesenteric artery
- Suprarenal arteries
- Renal arteries
- Gonadal (testicular or ovarian) arteries
- Inferior mesenteric artery
- Common iliac arteries
What are the 6 arteries of the pelvis and lower limbs
- Internal iliac arteries
- External iliac arteries
- Femoral artery
- Popliteal artery
- Anterior tibial artery
- Posterior tibial artery
How many veins enter the right atrium?
3
All medium and large arteries have ________ locations
Deep
What are multivein bundles called?
Venous plexuses
In areas with unusual patterns of venous plexuses, what drains the areas?
- Dural sinuses
- Hepatic portal system
Where does the superior vena cava return blood from?
Body regions superior to the diaphragm
Where does the inferior vena cava return blood from?
Body regions inferior to the diaphragram
What chamber of the heart does the superior and inferior vena cava join?
Right atrium
What are the 4 dural sinuses?
- Super and inferior sagittal sinuses
- Straight sinus
- Transverse sinus
- Sigmoid sinus
What is the functional of the internal jugular vein?
Drains blood from brain
Where does the internal jugular veins lie?
Superiorly it lies lateral to the internal carotid artery; inferiorly it lies lateral to the common carotid artery
What is the function of the external jugular veins?
Tributaries drain the scalp and empty into the subclavian vein
What are the 3 veins of the thorax?
- Azygos vein
- Hemiazygos vein
- Accessory hemiazygos vein
With what paths and names do the deep veins share?
Companion arteries
What are the 4 superficial veins of forearm?
- Cephalic Vein
- Basilic Vein
- Median Cubital Vein
- Median Vein of the Forearm
What do superficial veins form frequently?
Anastomese
Which vein is used to obtain blood of administer IV fluids?
Median cubital vein
What are the 5 veins of the abdomen?
- Lumbar veins
- Gonadal (testicular or ovarian) veins
- Renal veins
- Suprarenal veins
- Hepatic veins
What is the hepatic portal system?
Specialized part of the vascular circuit
What are the functions of the hepatic portal system?
Picks up digested nutrients and delivers it to the liver for processing
How many capillary beds does the hepatic portal system have? Where are they located?
2 beds; located in stomach/intestines & liver sinusoids
What are the 3 tributary veins of the hepatic portal vein?
- Superior mesenteric vein
- Splenic vein
- Inferior mesenteric vein
What scarring and degeneration of liver leads to what?
Blockage of liver sinusoids
What does blockage of liver sinusoids do?
Raises blood pressure in hepatic portal system (leads to portal hypertension)
What does portal hypertension lead to?
Emergency anastomoses for portal blood
What are the 3 main portal systemic anastomoses?
- Veins of inferior esophagus
- Hemorrhoidal veins
- Veins of superficial abdominal wall
What are the 2 superficial veins?
- Great saphenous vein
- Small saphenous vein
Where does the great saphenous and small saphenous vein empty into respectively?
- Great saphenous vein - Empties into Femoral vein
- Small saphenous vein - Empties into Popliteal vein
What are 5 disorders of the blood vessels?
- Aneurysm
- Deep vein thrombosis of the lower limb
- Venous disease
- Microangiopathy of diabetes
- Arteriovenous malformation
By which month are all the major blood vessels in place?
3
Where does the fetus supply blood to?
Placenta
Very little blood is sent through the ______________ for fetuses
pulmonary circuit
Where do umbilical vessels run?
Umbilical cord
What blood vessels in fetuses are paired vs unpaired?
Umbilical arteries - paired
Umbilical veins - unpaired
Name 4 fetal structures
- Ductus venosus
- Ligamentum teres
- Ligamentum venosum
- Medial umbilical ligaments
As the fetus grows, what changes/”shunts” away from the pulmonary circuit?
Foramen ovale and ductus arteriosus
When does Atherosclerosis begins? When does its consequences become evident? List both male vs female
Begins in youth; evident in middle to old age
Between ages 45 and 65, more males experience atherosclerosis than females
