Blood Vessels Flashcards
What are the five main blood vessels?
Arteries Arterioles Capillaries Venules Veins
What builds up the structure of blood vessels? (3)
Tunica Externa
Tunica Media
Tunica Interna
What is the Tunica Externa?
The outer fibrous sheath formed of elastin and collagen
What is the Tunica Media?
The middle layer of smooth muscle and elastic tissue
What is the Tunica Interna?
The smooth lining of squamous epithelium in the centre of blood vessels.
What is the role of arteries?
They take oxygenated blood away from the heart and delivers it to the capillaries.
What is the exception for the role of arteries?
The pulmonary artery which carries blood deoxygenated blood away from the heart to the lungs to be oxygenated.
What are the different types of artery in the body?
Carotic artery Radical artery Femural artery Aorta Brachial artery Pulmonary artery
What is the role of precapillary sphincters?
It is a band of smooth muscle that adjusts and controls blood flow into capillaries
What is the role of capillaries? (3)
Links the arterial and venous systems
Allow the interchange of gases and the transfer of nutrients to and waste products
Single layer of cells (short diffusion pathway)
What is the 3 different kinds of capillaries?
Continuous
Fenestrated
Sinusoid
What kinds of substances are exchanged through a semi-permeable membrane?
Glucose Fatty acids Amino acids (protein) Gases Vitamins Minerals
What is tissue fluid?
It is the fluid that fills the space between the cells
It is formed when plasma in the blood is forced through the gaps in the capillary walls except for those components that are too large
What is osmotic pressure?
It’s pressure that pulls fluid back in via the venous system
What is hydrostatic pressure?
The pressure blood is under as it enters the capillaries due to the search of blood as the heart contracts.
What is oncotic pressure?
The tendency of water to move into the blood by osmosis.
What is the two ends of the capillary called?
Arterial end and venous end
What is the role of the venous system?
The deoxygenated blood from the capillaries and delivers it to the heart
What is the exception for the venous system? (Veins)
The pulmonary vein as it carries oxygenated blood from the lungs to the heart
What are the different veins in the body?
Vena cava Pulmonary vein Jugular vein Hepatic vein Renal vein Popliteal vein
Factors that affect the diameter of blood vessels?
Vasodilation Vasoconstriction Medicines Drugs Alcohol Temperature
What is the autonomic nervous system?
It controls the smooth muscles in the arteries and veins
It controls involuntary functions in the body including heart beat
Where does the nerves from the autonomic nervous system come from?
The vasocentre in the medulla oblongata
What does the autonomic nervous system divide into?
The sympathetic and parasympathetic nervous system
What is the role of the sympathetic nervous system? (5)
It has a role in the fight or flight response
It is response for regulating the body’s unconscious actions
It is responsible for the reflexive, involuntary responses of the body
Helps regulate internal processes
It dilates and accelerates different parts of the nervous system
What is the role of the parasympathetic nervous system? (4)
It is response for regulating the body’s uncsonsious actions.
It is response for stimulate of “rest-and-digest” etc
It is the relaxation response
It contracts and slows down responses initiated by the sympathetic nervous system
What is systolic blood pressure? (4)
It is the first number recorded when blood pressure is taken
(120/80 mmHg - 120 is the systolic blood pressure)
It is due to the discharge of blood from the heart into the aorta
It is the pressure of the blood in the arterial system when the blood is pushed into the aorta
120mmHg
What does mmHg unit stand for?
Millimetres of Mercury
What is blood pressure?
It is the pressure of circulating blood on the walls of the blood vessels. Most of the pressure is due to the contraction of the heart
What is the normal systolic pressure?
Below 120
What is diastolic blood pressure? (3)
It is the second number (120/80 mmHg - 80 is diastolic)
It is the pressure in the arteries when the heart rests between beats
This is the time when the heart fills with blood and gets oxygen
What is normal diastolic pressure?
Lower than 80 (ranges from 60-80)
What factors determine blood pressure?
Cardiac output and arteriolar (peripheral) resistance
What is the phrase for organs that can self-regulate blood flow?
Auto-regulation
What are baroreceptors?
They detect pressure
what levels blood pressure affect baroreceptors? And where does this occur?
Baroreceptors in the aortic and carotid sinuses are stimulated when there is high and low blood pressure
What do baroreceptors do in terms of responding to blood pressure? (3)
They send information to the CVC
During high blood pressure, the CVC sends parasympathetic stimuli to the heart (slows) and reduces sympathetic stimulation to the blood vessels (vasodilation)
The opposite occurs for low blood pressure
What is the role of carotid sinuses?
The carotid sinus in the carotid arteries monitor the pressure of blood delivered to the brain.
It is the centre of the carotid sinus reflex
How does the baroreceptors in the carotid bodies respond to high blood pressure? (4)
The baroreceptors in the carotid bodies detect the change in blood pressure
Impulses are transported across the glossopharygeal nerve
The impulse then reaches the cardio-inhibitory centre in the medulla
The impulse then travels along the vagus nerve and reduces heart rate
What is the role of the aortic sinus?
The aortic sinus in the arch of the aorta monitors the pressure of blood as it leaves the heart.
It is the centre of the aortic sinus reflex
How does the baroreceptors in the aortic bodies respond to high blood pressure? (4)
The baroreceptors in the aortic bodies detect high blood pressure
An impulse is then sent across the vagus nerve
The impulse then reaches the cardio-inhibitory centre in the medulla
The impulse then travels along another vagus nerve reducing the heart rate
What does the chemoreceptors respond to and where are they?
Chemoreceptors in the aorta and carotid bodies and also in the medulla respond to rising carbon dioxide and decreasing oxygen
What do chemoreceptors do in response to blood pressure?
They send impulses to the CVC, which increases sympathetic stimulus to the heart and blood vessels
Only occurs when severe disruption to respiratory and a fall in systolic BP >80mmHg
What does the hypothalamus do?
It keeps the body in homeostasis
It controls things like temperature
What factors affect pulse rate?
Medication Temperature Age Exercise Disease Drugs Posture Emotional state
What factors affect respiratory rate?
Age Pain Emotion Resistance from air passages (eg.asthma) Fever Elasticity of the lungs Chemical changes
