Anatomy Flashcards
What is the cardiovascular system comprised of?
Arterial System
Heart
Venous System
What are the 4 cardiac valves and where are they located?
- Tricuspid valve = RA + RV
- Pulmonary valve = RV + Pulmonary Trunk
- Mitral valve = LA + LV
- Aortic Valve = LV + Aorta
Describe the journey of blood through the heart
Blood flows in through the Superior or Inferior Vena Cava into the right atrium of the heart, through the tricuspid valve into the right ventricle.
Blood flows through the Pulmonary valve into the pulmonary trunk into the lungs and back through the pulmonary artery.
It passes into the left atrium through the mitral valve into the left ventricle through the aortic valve into the aorta.
What are the 3 layers of the heart (From external to internal)
- Epicardium (external)
- Myocardium
- Endocardium (Internal)
What happens in systole?
Contraction
What happens in diastole?
Relaxation
What chamber forms the right border of the heart?
Right atrium
What chamber forms the anterior border of the heart?
Right Ventricle
What chamber forms the posterior border of the heart?
Left Atrium
What chamber forms the left border of the heart?
Left Ventricle
What are the 3 layers of blood vessels (internal to external)?
- Tunica Intima
- Tunica Media
- Tunica Adventitia
Describe the conduction system of the heart.
- Electrical impulse starts at the SA node (Both atria contract)
- Travels to AV node at atrioventricular septum
- Travels down right and left bundles in interventricular septum
- Spreads out to myocardium through conducting fibres (both ventricles contract)
Describe features of arteries
- High pressure
- Pulsatile
- Carry oxygenated blood
What is an end artery?
only arterial blood supply to a given area of the body. Occlusion of an end artery results in infarction.
What is infarction?
irreversible cell death due to hypoxia.
Describe sympathetic Tone?
Sympathetic Tone is the background low level of contraction of smooth muscle in arterioles. This is due to tonic conduction of action potentials to arterioles by sympathetic nerves.
What is vasodilation?
Vasodilation is relaxation of the smooth muscle and widening of the lumen to increase blood flow.
What is vasoconstriction?
Vasoconstriction is the contraction of smooth muscle to reduce blood flow to the organ/tissue.
What is an anastomosis?
Anastomosis is where arteries connect with each other without intervening capillary network. This provides alternative routes for blood to flow to supply the cells distal to an arterial occlusion.
What is an example of an anastomosis?
The Circle of Willis in the brain
What are collateral arteries?
Alternative routes in an anastomosis.
What is a disadvantage of collateral arteries?
One disadvantage is that collaterals bleed from both sides of the cut.
What are the branches of the aorta?
- Brachiocephalic trunk
- Left common carotid artery
- Left subclavian artery
Describe features of veins
- Low pressure
- Deoxygenated blood
- Non-pulsatile
How is venous blood pumped back towards the heart?
- Venous valves
- Skeletal muscle pump
- Venae Comitantes - Arterial pulsations pushes venous blood along towards the heart.
What are the 2 main venous systems?
Hepatic Portal Venous System
Systemic Venous System
What is the function of the hepatic portal venous system?
drains blood from absorptive parts of the GI tract and associated organs to the liver for cleaning.
What is the function of the systemic venous system?
drains venous blood from all other organs + tissues into the superior or inferior vena cava.
What do lymphatic capillaries collect?
Tissue Fluid
What is the tissue fluid called once it has entered the lymphatic capillaries?
Lymph
What happens to lymph once its in the lymphatic capillaries?
Lymphatics can carry lymph through lymph nodes.
Where do superficial lymphatics drain into?
deep lymphatic vessels.
What is the only lymph vessel large enough to see on dissection?
Thoracic Duct
When can lymph nodes be palpated?
When fighting an infection or cancer
What does the axial skeleton include?
bones of the skull, neck and trunk
What does the appendicular skeleton include?
bones of the pectoral girdle, upper limbs, pelvic girdle and lower limbs.
What are the 3 types of bony features?
- Functional - best shape for the job
- An adjacent structure applying force - moulding it’s shape.
- An adjacent structure developing at the same time - grows around the structure
Describe bone.
hard connective tissue, functions include: - support and protection, - calcium metabolism, - red blood cell formation etc.
Describe cartilage
less rigid than bone.
Located where mobility is required.
Describe a synovial joint
the ends of bones are encased in smooth cartilage. E.g., Hinge - elbow, Saddle - carpometacarpal, ball and socket - hip
Describe a primary cartilaginous joint
bones are connected by hyaline cartilage e.g., growth plates
Describe a secondary cartilaginous joint
a flat disk of fibrocartilage connect bones e.g., pubic symphysis
Describe a fibrous joint
adjacent bones are strongly united by fibrous connective tissue e.g., sutures on the skull.
Function of tendons?
attach the muscle to bone.
What is an aponeurosis?
a flattened tendon and attaches to soft tissue rather than bone.
Describe the flexion withdrawal reflex
- touch something dangerous
- sudden withdrawal
- nerve connections are at spinal cord level not brain.
Describe the stretch reflex?
- tendon hammer used to apply a brief, sudden stretch to the muscle via the tendon
- reflex is twitch of the muscle belly
Describe the reflex arc?
- sensory nerve from muscle detects stretch and tells the spinal cord.
- Synapse in the spinal cord between sensory and motor nerves
- Motor nerves from spinal cord message to muscle to contract
What does a normal stretch reflex indicate?
indicates that the following are functional:
- the muscle
- sensory nerve fibres
- motor nerve fibres
- spinal cord connections
- neuromuscular junction
- descending controls from the brain
Describe paralysis?
a muscle without a functioning motor nerve supply is “paralysed”. It cannot contract. It has reduced tone