Science Flashcards
What are the three body planes?
Sagittal/Lateral, Coronal/Frontal, Axial/Transverse
What is the difference between medial and lateral?
Medial means nearer to the midline of the body. Lateral refers to structures further away from the body’s midline, at the sides.
In anatomical position, the thumb is lateral to the little finger, and the little finger is medial to the thumb.
What does proximal mean and what term of anatomic direction is the opposite?
Proximal refers to structures closer to the center of the body. Distal refers to structures further away from the center of the body.
The knee is distal to the hip and the hip is proximal to the knee.
What do the terms anterior, posterior, superior, and inferior mean, respectively?
-Anterior refers to structures in front.
-Posterior refers to structures behind.
-Superior means above, or closer to the head.
-Inferior means below, or closer to the feet.
What are the abdominal quadrants?
RUQ | LUQ
—— | ——
RLQ | LLQ
The abdomen may be divided into four quadrants with the umbilicus.
(Naval) at the center, helping to identify the position of organs.
What structures compromise the respiratory system and what is its primary function?
It includes the nose, mouth, nasal cavity, sinuses, pharynx, larynx, trachea, bronchial tree, and lungs. These organs facilitate the delivery of oxygen to the cells of the body for use in cellular respiration and help remove waste in the form of carbon dioxide.
Secondary functions of the respiratory system include pH regulation of the blood, thermoregulation, odor detection, and the production of speech.
What is the generalized structure of the lungs?
The lungs are spongy, porous organs that occupy most of the thoracic cavity. A serous membrane called the pleura lines the thoracic cavity (parietal pleura) as well as the surface of the lungs (visceral pleura). The three-lobed right lung is separated from the two-lobed left lung by the mediastinum. The trachea forks into primary bronchi which enter the left and right lung (along with blood and lymphatic vessels) at a region called the hilum.
What are the divisions of the passage to the lungs?
The trachea splits into two primary bronchi (one for each lung), which split repeatedly into secondary bronchi, tertiary bronchi, and bronchioles to form the bronchial tree. The terminal bronchioles further divide into respiratory bronchioles, which are characterized by the presence of some alveoli. The respiratory bronchioles lead into alveolar ducts, which terminate in alveolar sacs.
What is the general mechanism for breathing?
When the diaphragm and external intercostals contract, the volume of the thoracic cavity increases, and the rib cage and sternum elevate and expand outward. Then increase in volume results in a decrease in intrapleural pressure, and air enters the lungs in a process called inspiration. As the volume of the thoracic cavity decreases, intrapleural pressure increases, and air leaves the lungs in the more passive process of expiration.
How is the circulatory system involved in thermoregulation?
Thermoreceptors detect changes in temperature and send impulses to the hypothalamus, which then sends signals to the effectors (smooth muscles that surround cutaneous arterioles). If the body temperature is too warm, the smooth muscle relaxes, and the arterioles dilate to allow more blood to flow through the capillary beds near the surface of the skin, so more heat is lost to the surroundings. If the temperature is too cool, the opposite occurs.
What are the three layers of the heart?
The outer layer is the epicardium, which protects the heart and secretes lubricating serous fluid. The middle layer is the muscular myocardium, which contracts to pump blood. The innermost layer is the endocardium, which lines the chambers and valves.
What are the different valves of the heart and their respective functions?
The tricuspid valve (right AV valve) prevents backflow into the atrium when the ventricle contracts. The pulmonary semilunar valve prevents the return of blood into the right ventricle. The bicuspid valve (also called the left AV valve, or mitral valve) prevents blood from entering the left atrium when the ventricle contracts. The aortic semilunar valve stops the backflow of blood into the left ventricle as it leaves through the aorta.
What is blood pressure, and what do the two numbers indicate?
The force per unit area that is exerted by the blood on the walls of the vessels. The first number refers to the systolic pressure, or the maximum pressure when the ventricles contract, forcing blood into the aorta and pulmonary trunk. Diastole is the period in which the ventricles relax and blood pressure is at its lowest point; diastolic pressure is the bottom number.
What are the primary differences between the systemic and pulmonary circulation?
Because the systemic circuit is much longer than the pulmonary circuit, blood pressure is higher. In the systemic circuit, blood in the arteries carries more oxygen than blood in the veins (the opposite is true for pulmonary circulation). When oxygen levels are low, vessels in the systemic circuit dilate to promote blood flow to tissues that need it, but in pulmonary circulation low blood oxygen triggers vasoconstriction, which redirects blood to better ventilated parts of the lung.
What are the components of the ECG, and what cardiac events do they correspond to?
The P wave represents depolarization of the atria on an ECG. This is followed by the QRS interval, which represents depolarization of the ventricle. Next follows the ST segment and T wave, corresponding to repolarization of the ventricle. A small U wave may follow the T wave and represents further repolarization of the ventricle.
