MEDICAL A&P

Good blood supply.

2 x hemispheres

4 sections – cerebrum, diencephalon, cerebellum, brain stem.

3 layers – meninges, with spaces between; dura mater, arachnoid mater, pia mater.

Ventricles surrounded by CSF.

Millions of neurones.

Surrounded by 22 bones

Physiology

20% of body’s O2, 25% of glucose.

Controls voluntary and involuntary nerves impulses to and from body.

Maintains homeostasis.

CSF absorbs shock ad lubricates.

Different areas control different things: cerebrum controls conscious thought; brainstem is responsible for levels of consciousness; diencephalon for regulation of temperature;

5-6 litres of blood. 3 types of blood cell (RBCs – erythrocytes; WBC leucocytes; platelets thrombocytes).

RBCs are concave and have no nucleus and are responsible for O2 uptake and transport. They are 25% of lood volume.

Body has arteries, veins, arterioles, venules and capillaries. Gas exchange takes place in capillaries. All vessels have 3 layers – tunica adventitia (tough layer), tunica media (smooth muscle) and tunica intima, (thin) with a lumen in the middle.

RBCs transport O2 and other gasses.

Arteries carry oxygenated lood from the heart. Veins carry deoxygenated blood to the heart. Capillaries connect veins to arteries, ad this is where gas exchange takes place. WBCs are the body’s defense from infections.

Blood maintains homeostasis and temperature.

Lies in the mediastinum, behind sternum, between lungs and above the diaphragm.

Approx 10cmx9cmx6cm (lwd).

Comprised of an apex and base; the base is at the top.

At an angle of 60 degres.

Wall is comprised 3 layers – outer fibrous pericardium; middle muscular myocardium; inner smooth endocardium.

4 chambers – 2 x atria (recive blood from vena cava and lungs), 2 x ventricles (reveive blood from atria). RV pumps blood to the lungs. LV pumps blood to the body via the aorta.

Double pump, to the body and to the lungs. Allows tissue perfusion.

Brain controls the heart rate in the MO, where chemoreceptors measure heart rate and baroreceptors measure BP.

A electrical pathway through the myocardium regulates a heart beat, whereby the myocardium fibres shorten as the impulse travels through, facilitating a contraction, ejecting blood from it’s chambers.

Between the pericardial layers is a potentil space with a fine film of serous fluid, facilitating a friction free movement of the heart.

Anatomy

Organ of the digestive system, located in the abdominal cavity, posterior to the stomach, in the upper-left quadrant. 15 cm long. 60-100g weight.

Physiology

Sends signals to the liver to release glucagon as glucose. Has an endocrine and exocrine function. Endocrine – sends hormones to the blood such as insulin and glucagon. Exocrine – secretes juices iinto the duodenum. Alpha cells tell the liver to release glucose from glucagon. Beta cells tell insulin to be released, which regulates blood glucose levels.

Physiology

Ventilation of the lungs is controlled by the diaphragm and intercostal muscles. When contracted down, the diaphragm lowers pressure in the pleural cavity, drawing air into the lungs. Gas exchange takes place in the alveoli, via partial pressure and Dalton’s Law, meaning gasses are exchanged via diffusion from alveoli into the capillary network. Blood is oxygenated in this way.

The abdominal cavity is inferior to the thoracic cavity and superior to the pelvis. It is separated from the thoracic cavity by the diaphragm. There are 4 quadrants of the abdominal cavity. It contains the digestive organs; these are protected by a serous membrane called the peritoneum. There are 3 areas of the abdominal cavity – the abdomen, pelvic and retro-peritoneal.

The appendix is a hollow tube, attached to the caecum. It is 8cm long and lies in the LRQ.

The abdomen covers many organs including the spleen, liver, stomach, large and small intestine, gall bladder, appendix and pancreas. The peritoneum covers and protects many of these organs. Most of the GI tract is within the abdomen, and is responsible for the absorption ad digestion of food. The upper GI tract runs from mouth to duodenum. The lower GI tract runs from duodenum to anus.

The appendix has no function in humans, and is an evolutionary hangover.

The abdominal cavity is inferior to the thoracic cavity and superior to the pelvis. It is separated from the thoracic cavity by the diaphragm. There are 4 quadrants of the abdominal cavity. It contains the digestive organs; these are protected by a serous membrane called the peritoneum. There are 3 areas of the abdominal cavity – the abdomen, pelvic and retro-peritoneal.

Upper GI tract – mouth, pharynx, oesophagus, stomach, duodenum. Lower GI tract – small and large intestine, jejunum (2.5m long), ilum (3m long), rectum, anus.

The abdomen covers many organs including the spleen, liver, stomach, large and small intestine, gall bladder, appendix and pancreas. The peritoneum covers and protects many of these organs. Most of the GI tract is within the abdomen, and is responsible for the absorption ad digestion of food. The upper GI tract runs from mouth to duodenum. The lower GI tract runs from duodenum to anus.The GI tract is highly vascular