Anatomy Flashcards
What are the two sides of the heart divided by and why is this needed?
The septum, without this there would be the mixing of blood which would reduce the efficiency of the heart.
How is heart location described?
- In the thoracic cavity.
- Deep to the sternum.
- Deep to costal cartilages.
- Protected by ribs, vertebrae and sternum.
- Between the lungs (mediastinum)
- More on the left side than the right.
Describe the three layers of the heart
1) Epicardium- this is external, visceral serous pericardium
2) Myocardium- middle, muscle layer
3) Endocardium- internal lining that is continuous with endothelium of blood vessels connecting with the heart.
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Name the 4 cardiac valves and describe location
Pulmonary valve (between right ventricle and pulmonary trunk) Tricuspid valve (between right atrium and right ventricle) Mitral/bicuspid valve (between left atrium and left ventricle) Aortic valve (between left ventricle and aorta)
What do valves prevent?
The backwards flow of blood
Describe the mediastinum and where the heart is
- The Mediastinum is the area that lies in between the lungs.
- It is divided into the inferior and superior mediastinum.
- The inferior mediastinum is further divided into anterior, middle and posterior.
- The heart is located in the middle mediastinum.
Describe the pericardium
• The Pericardium forms the boundaries of the middle mediastinum and is the tissue surrounding the heart.
• It has two layers:
1) The fibrous pericardium- a thick outer layer that prevents overfilling.
2) Serous Pericardium- an inner membranous layer that secretes serous fluid. It reflects back on itself, it stops friction. There is a visceral layer of the serous pericardium that covers the heart and a parietal layer that lines the fibrous pericardium
What functions does the fibrous skeleton of the heart provide?
- Keeps orifices of valves patent
- Forms the fibrous rings of the cardiac valves
- Forms an electrical insulator by separating conducting impulses of atria and ventricles allowing one normal route for electrical conduction in the heart
How does the heart’s conduction system work?
Electrical impulse starts spontaneously at SA node (pacemaker), travel through cardiac muscle of atria and cause them to contract. Travel down through the septum and spreads out to myocardium through conducting fibres causing the ventricles to contract
What is fibrillation?
The uncoordinated contraction of the cardiac muscle
What are external factors that can also affect heart rate and force of contraction?
Nerves that supply the heart e.g. sensory nerves and motor nerves- these include sympathetic nerves that speed the heart up and increase force of contraction. Circulating hormones such as adrenaline can also have an effect.
What does pulmonary circulation refer to?
The circulation of blood in which deoxygenated blood is pumped from the heart to the lungs and oxygenated blood is returned to back to the heart.
Describe the route blood takes through the heart
Deoxygenated blood is taken back to the heart by the vena cava and into the right atrium and the ventricle, the pulmonary artery then takes the deoxygenated blood to the lungs where it is oxygenated and returned to the heart by the pulmonary vein. It is then pumped through the left atrium and ventricle before being pumped around the body by the aorta.
What is systemic circulation?
This is what occurs between the heart and the entire body.
What are great vessels?
Vessels directly connected to a chamber of the heart.
Why are arterioles said to have sympathetic tone?
Only the sympathetic nervous system effects blood vessels, as only contraction is active, relaxation is simply the act of not contracting so does not involve the parasympathetic system.
What are the four parts of the aorta?
Arch of the aorta, ascending aorta, thoracic aorta, abdominal aorta.
What is the blood supply to the brain provided by?
The circle of Willis.
What is the blood brain barrier created by and what is the purpose?
Tight junctions between brain capillary endothelial cells and this prevents the diffusion of some substances from capillary into the brain.
What are end arteries?
The only arterial blood supply to a given area of the body. The hands have true end arteries and the heart has false end arteries.
What is infarction
irreversible cell death due to hypoxia (lack of oxygen) caused by loss of arterial blood supply.
What does the ascending aorta branch into and what does the arch of the aorta branch into?
Ascending: left and right coronary artery
Arch: the brachiocephalic trunk, left common carotid artery, and left subclavian artery.
What does the abdominal aorta bifurcate into?
Common iliac arteries.
Name 7 peripheral pulses that can be tested?
- Carotid Pulse (in the neck)
- Brachial Pulse (upper limb)
- Radial Pulse (upper limb)
- Femoral Pulse (lower limb)
- Popliteal Pulse (lower limb)
- Posterior Tibial Pulse (lower limb)
- Dorsalis Pedis Pulse (foot)
What are the two main venous systems?
The hepatic portal venous system (drains blood from absorptive parts of GI tracts) and the systemic venous system (drains blood from all other organs and tissues).
What is the circulatory system made up of?
The cardiovascular and the lymphatic system.
What type of bone marrow makes red blood cells?
Red bone marrow- As you grow up this marrow turns yellow but in cases of extreme blood loss there is the possibility for it to revert back and make red blood cells.
What is the the Periosteum
A fibrous connective tissue sleeve surrounding bone.
What are the two types of bone?
Compact (cortical) and spongy (trabecular) bone.
Explain endochondral ossification
This explains how long bones grow. An initial small, hyaline cartilage version grows and turns into bone (ossifies). When the growth plate of hyaline cartilage finally ossifies, bone growth ceases and we have attained our final height.
Explain the five main categories of bone shape
1) Flat Bones: these are protective.
2) Long Bones: these are tubular and are longer in one dimension than in the other.
3) Irregular Bones: these are weird shapes e.g. vertebrae.
4) Sesamoid Bones: these form within a tendon, function is to restrict the amount of friction in the tendon.
5) Short Bones: these are cuboidal.
Explain reduction and fixation of a fracture
For the fracture to heal properly the broken ends must be brought together approximating their normal position. This is called reduction of the fracture. Reduction can be done surgically if needed. Surgical fixation can also be carried out which involves using titanium plates & screws to hold the ends of the bone in correct alignment.
What happens during bone healing?
The surrounding fibroblasts (connective tissue cells) proliferate and secrete collagen which forms a collar of callus to hold the bones together.
Name the parts of the axial and Appendicular skeleton
Axial is skull, spine, ribs and sternum
Appendicular is pectoral girdle, upper limbs, pelvic girdle, lower limbs.
What is the cranial vault?
The space in the skull within the neurocranium, occupied by the brain.
What is a le fort fracture?
A fracture of the mid face, there are three grades depending on severity.
Describe the vertebral column
There are five regions and 33 vertebrae in total:
- 7 cervical (C1-C7) these are the vertebrae of the neck.
- 12 thoracic (T1-T12) these attach to ribs.
- 5 lumbar (L1-L5) vertebrae of the back.
- 5 sacral (fused to form 1 sacrum).
- 4 coccygeal (fused to form 1 coccyx).
What are the three types of muscle?
1) Cardiac- involuntary and striated, allows the heart to beat.
2) Smooth muscle- involuntary and non-striated.
3) Skeletal muscle- voluntary, this allows conscious movement, it is very striated.
What allows skeletal muscles to move a joint?
They must cross the joint.
What is an aponeurosis
A flattened tendon most commonly associated with flat muscles. They attach muscle to soft tissue rather than bone.