UNIVERSIDAD NACIONAL DEL SUR EXAMEN7 DE"SUFICIENCIA DE IDIOMA INGLS

Medicina

NOMBRE Y APELLIDO: ...................................................................................................... .

LU ................................ .. FECHA: .......................... .

TEXTO 1

A. Lee rpidamente el texto, sin usar diccionario, para obtener una idea general.

B. Vuelve a leer cada prrafo detenidamente y responde las preguntas en espaol:

1. Qu sucede cuando la sangre fluye a travs de los pulmones?

2. Completa la oracin: "Cuando la sangre llega al tracto gastrointestinal, ... ".

3. Qu hace el hgado con las sustancias que no son utilizadas por las clulas?

4. Cmo colabora el sistema msculo-esqueltico con las funciones homeostticas?

5. Describe la funcin de los riones.

6. Cmo se compone el sistema nervioso central? Cul es la funcin del cerebro?

7. "El sistema nervioso y el sistema hormonal no cumplen las mismas funciones." Indica si esta afirmacin es verdadera o falsa. Justifica tu respuesta.

8. De qu manera la reproduccin ayuda a mantener las condiciones estticas?

"HOMEOSTATIC" MECHANISMS OF THE MAJOR FUNCTIONAL SYSTEMS

ORJGIH OF NUTRIENTS IN THE EXTRAC~J.1.ULAR FLUID

The Respiratory System. Figure 1-1 shows that each time the blood passes through the body it also fiows through the lungs. The blood picks up oxygen in the alveoli, thus acquiring the o:rygen needed by the cells. The membrane between the alveoli and the lumen of the pulmonary capillaries is only 0.4 to 2.0 micrometers in. thickness, and oxygen diffuses through this membrane into the blood in exactly the same manner that water and ions diffuse through the tissue capillaries.

The Gast rointestinal Tract. A large portian of the blood pumped by the heart passes also through the walls of the gastrointestinal organs. Here di.fferent dissolved nutrients, including carbohydrates, fatty acids, amino acids, and others, are absorbed into the ertracellular fluid.

The Liver and Other Organs That Perform Primarily Metabolic Function.s. Not all sub-stances absorbed from the gastrointestinal tract can be used in their absorbed form by the cells. The liver changes the chemical compositions of many of these to more usable forms, and other tissues of the body-the fat cells, the gstrointestinal mucosa, the kidneys, and the endocrine glands- help to modify the ab-sorbed substances or store them until they are needed at a later time.

The Musculoskeletal System. Sometimes the question is asked: How does the musculoskeletal sys-tem fit into the homeostatic functions of the body? The answer to this is obvious and simple: Were it not for this system, the body could not move to the appro-priate place at the appropriate time to obt:ain the foods required for nutrition. The musculoskeletal systcm also provides motility for protection against advcrse surroundings, without which t:he en tire body, and al.ong with it al! the homeostatic mechanisms. could be destroyed instantaneously.

REMO VAL OF MET ABOUC ENP PRODUCS

Removal of Carbon Dioxide by the Lungs. At the same time that biood picks up oxygen in the lung"s,

carbon dioxide is released from the blood into the al-veoli, and the respiratory movement of air into and out of the alveoli carries the carbon dioride to the atmosphere. Carbon dio:ride is the most abundant of all the end products of metabolism.

The Kidneys. Passage of the blood through the kidneys removes most substances from the plasma that are not needed by the cells. These substances include especially di.fferent end products of cellular metabolism and excesses ofions and water that miaht

" ha ve accumulated in the ertracellular fluid. The kid-neys perform t:heir function by fusi filterina lar"e

' ' t:7 o quantities of plasma through the glomeruli into the tubules and then reabsorbing into the blood those

substances needed by the body, such as glucose, aminc. acids, appropriate amounts ofwater, and many ofthE. ions. However, most of the substances not needed by the body, especially the metabolic end products such as urea, are poorly reabsorbed and, instead, pass on through the renl tubules into the urine.

RE~ULAT10N OF BODY FUNC710NS The Nervous System. The ner . ..-ous svstem is

composed of three majar parts: the sensory- portian, the central neruous system (or integratiue portian). and the motor portian. Sensory receptors detect the state ofthe body or the stateofthe surroundings. For instance, receptors present everywhere in the skin apprise one every time an object touches that person at any point. The eyes are sensory organs that give one a visual image of the surrounding area. The ears also are sensory organs. The central nervous svstem is composed of the brain and spinai.cord. The brain can store information, generate thoughts, create ambi-tion, and determine reactions the body performs in response to the sensations. Appropriate signals are then transmitted through the motor portian of the nervous system to carry out the person's desires .

A large segment of the nervous system is called the autonomic system. It operates at a subconscious leve!. and controls many functions of the interna! oraans including the action of the heart, the moveme;ts ot the gastrointestinal tract, and the secretion by dilfer-ent glands.

The Hormonal System of Regulation. Located in the body. are eight majar endocrine glands that secrete chemical substances, . the hormones. Hor-mones are transported in the extrace!lular fluid to ai! parts of the body to help regulate cellular function. For instance, thyroid hormone increases the rates of rnost chemical reactions in all cells. In t his wav thv-roid hormone heips to set the tempo ofbodil:.: ac~ivit~.-. Insulin controls glucose metabolism, adrenoco rtic~J hormones control ion and protein metabolism, a r. parathyroid hormone contrnls bone metaho!iscL Thus, the hormones are a system of regular. ic>n tn;_, , cumplemenr.s t hc: nerV(JUS system. T he ner'lc;us ; ;:, te m, n general, re,n.1lates mainly muscular and sec~~ . tory activities of the body, whereas the hormonal :; v~ -tem regulates mainiy the metabolic functions. .

REPRODUCT10N Reproduction sometimes is not considered to be a

homeostatic function. However, reproduction does help to maintain static conditions by generating new beings to take the place of ones that are dying. This perhaps sounds like a permissive usage of the term homeostasis, but it does illustrate that, in the final analysis, essentially all structures of the body are so organized that they help maintan the automaticity and the continuity of life.

TF.XTO 2

Lee cada prrafo y subraya las ideas principales. Elabora un resumen.en espaol que exprese esas ideas.en..forma clara y coherente.-NO-se-acepta-el-:.empleo-de-abreviaturas ni trminos en ingls_

LIVING VS. NONLIVJNG MATTER

Most living thlngs and organisms can be distinguished readily form nonliving materials by a few simple criteria: form and size, chemical cornposition. and organization, among others_

FORM AND SIZE. Each kind ofliving organism usually has a defmite fonn and characteristic size, within certain limits; most of them are also arranged as definite. individuals. A whale, a lea, or any com.mon plant is recognized by such features. Nonliving materials vary widely in such respects, as from a sand grain to a mountain ora drop of water to an ocean. CHEWCAL CO:MPOSffiON. Living organisms are composed chiefly of carbon, hydrogen, ox:ygen, and nitrogen in various but defmite proportions, together with small amounts of oth~r chemical elements. These materials are organized into complex organic molecules, often of great molecular weight, and collectively form the living substance or protoplasm. The same and other chernical elements occur as compounds in nonliving minerals, but the molecular weights are small. ORGANIZATION. The parts of each living organism are composed of complex microscopic cells, and these are assembled into interrelated systems for performing the life processes. The living plant or animal rearranges and recombines the chemical elemertts for its needs. Roclcs and minerals cannot recombine materials like a living system; any of their structural features such as crystal pattem depend pn the chemicals present and mode of formation. lYfETABOLISM_ Various vital processes, collectively known as metabolism, are constantly taking place within living organisrns - intake and use of food, r~spiration, secretion, and others_ Nonliving things have no metabolic changes. IRRITABILITY. The living organism and its parts react to changes in the environment. These act as stimuli that produce responses by the organism. Stimuli may be externa!, such as heat, light, moisture, pressure or contact, or else interna!. The degree of response is often disproportionate to that of the stimulus, and the organism is not permanently altered by the stimulus. Wben inanimate rnaterials react, there is a definite quantitative relation between the intensity of the environmental change and the reaction produced, as in the expansion of a metal by heat. REPRODUCTION. Each kind of living organism has the ability to duplicate itself in kind - pine seeds produce pine trees and not oaks, and chicken eggs yield little chicles and not ducklings or puppies. Organisms reproduce by using rnaterials within their bodies_ Nonliving things cannot reproduce_ GROWTII AND LIFE CYCLE. Living organisms grow by developrnent of new parts between or within older ones and may replace parts during life_ Each individual has a defmite Iife cycle- birth, growth, maturity, life span, and death. If nonliving things increase, they do so by externa! addition, as with crystals, and there is no orderly cycle of change_