BIO 235 Midterm Exam 2022

BIO 235 Midterm Exam 2022. In the anatomical position, the subject stands erect facing the observer with the head level and the eyes facing forward. The feet are flat on the floor and directed forward and the arms are at the sides with the palms turned forward. The lungs are located in the a) cranial cavity. b) vertebral cavity. c) abdominal cavity. d) pericardial cavity. e) pleural cavity. Which cavity is located inferior to the abdominal cavity? a) vertebral canal b) cranial cavity c) abdominal cavity d) pericardial cavity e) pelvic cavity Which cavity contains the heart? a) cranial cavity b) vertebral cavity c) abdominal cavity d) pericardial cavity e) pleural cavity Which plane divides the body into equal right and left halves? a) frontal b) midsagittal c) transverse d) oblique e) coronal Which plane divides the body into anterior and posterior portions? a) frontal b) sagittal c) transverse d) oblique e) midsagittal A transverse plane will cut a body or organ into a) anterior and posterior portions. b) left and right portions. c) superior and inferior portions. d) portions separated at an angle to its longitudinal axis. e) unequal left and right portions Which directional term means farther from the midline? a) medial b) anterior c) proximal d) deep e) lateral Which directional term means farther from the attachment of a limb to the trunk or farther from the origination of a structure? a) deep b) contralateral c) lateral d) cephalic e) distal Choose the directional term that would make the following sentence correct. The heart is _____ to the liver. a) inferior b) anterior c) contralateral d) superior e) superficial Choose the directional term that would make the following sentence correct. The sternum is _____ to the heart. a) posterior b) anterior c) inferior d) superior e) lateral Which of the following organs is not found in the abdominal cavity? a) stomach b) spleen c) liver d) gallbladder e) diaphragm 2. Basic Life Process: Growth Answer: Growth is an increase in body size that results from an increase in the size of existing cells, an increase in the number of cells, or both. In addition, a tissue sometimes increases in size because the amount of material between cells increases. In a growing bone, for example, mineral deposits accumulate between bone cells, causing the bone to grow in length and width. 3. Feedback systems and examples A feedback system or feedback loop is a cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored, reevaluated, and so on. Each monitored variable, such as body temperature, blood pressure, or blood glucose level, is termed a controlled condition. Any disrup- tion that changes a controlled condition is called a stimulus. A feedback system includes three basic components: a receptor, a control center, and an effector Receptor: is a body structure that monitors changes in a controlled condition and sends input to a control center (afferent pathway) Control Center: evaluates the input it receives from receptors, and generates output commands when they are needed (efferent pathway) Effector: is a body structure that receives output from the control center and produces a response or effect that changes the controlled condition. A negative feedback system reverses a change in a controlled condition. Consider the regulation of blood pressure. Blood pressure (BP) is the force exerted by blood as it presses against the walls of blood vessels. When the heart beats faster or harder, BP increases. If some internal or external stimulus causes blood pressure (controlled condition) to rise, the following sequence of events occurs. Baroreceptors (the receptors), pressure-sensitive nerve cells located in the walls of certain blood vessels, detect the higher pressure. The baroreceptors send nerve impulses (input) to the brain (control center), which interprets the impulses and responds by sending nerve impulses (output) to the heart and blood vessels (the effectors). Heart rate decreases and blood vessels dilate (widen), which cause BP to decrease (response). This sequence of events quickly returns the controlled condition—blood pressure—to normal, and homeostasis is restored. Notice that the activity of the effector causes BP to drop, a result that negates the original stimulus (an increase in BP). This is why it is called a negative feedback system. Positive Feedback Systems Unlike a negative feedback system, a positive feedback system tends to strengthen or reinforce a change in one of the body’s controlled conditions. In a positive feedback system, the response affects the controlled condition differently than in a negative feedback system. The control center still provides commands to an effector, but this time the effector produces a physiological response that adds to or reinforces the initial change in the controlled condition. The action of a positive feedback system continues until it is interrupted by some mechanism. Normal childbirth provides a good example of a positive feed- back system. The first contractions of labor (stimulus) push part of the fetus into the cervix, the lowest part of the uterus, which opens into the vagina. Stretch-sensitive nerve cells (receptors) monitor the amount of stretching of the cervix (controlled condition). As stretching increases, they send more nerve impulses (input) to the brain (control center), which in turn re- leases the hormone oxytocin (output) into the blood. Oxytocin causes muscles in the wall of the uterus (effector) to contract even more forcefully. The contractions push the fetus farther down the uterus, which stretches the cervix even more. The cycle of stretch- ing, hormone release, and ever-stronger contractions is interrupted only by the birth of the baby. Then, stretching of the cervix ceases and oxytocin is no longer released. Another example of positive feedback is what happens to your body when you lose a great deal of blood. Under normal conditions, the heart pumps blood under sufficient pressure to body cells to provide them with oxygen and nutrients to maintain homeostasis. Upon severe blood loss, blood pressure drops and blood cells (including heart cells) receive less oxygen and function less efficiently. If the blood loss continues, heart cells be- come weaker, the pumping action of the heart decreases further, and blood pressure continues to fall. This is an example of a positive feedback cycle that has serious consequences and may even lead to death if there is no medical intervention. As you will see in Chapter 19, blood clotting is also an example of a positive feedback system. These examples suggest some important differences between positive and negative feedback systems. Because a positive feedback system continually reinforces a change in a controlled condition, some event outside the system must shut it off. If the action of a positive feedback system is not stopped, it can “run away” and may even produce lifethreatening conditions in the body. The action of a negative feedback system, by contrast, slows and then stops as the controlled condition returns to its nor- mal state. Usually, positive feedback systems reinforce conditions that do not happen very often, and negative feedback systems regulate conditions in the body that remain fairly stable over long periods. A condition NOT regulated by a negative feedback loop would be: a) childbirth b) body temperature c) blood pressure d) heart rate e) blood sugar 4. Basic details of atom (proton, electron, neuron) and molecules Answer: Atoms- the smallest units of matter that retain the properties and characteristics of the element. Proton - positively charged Electron – negatively charged Neuron – uncharge (neutral) The three types of subatomic particles that are important for understanding chemical reactions in the human body 5. Structure of Phospolipids Phospholipids are amphipathic molecules, having both polar and non polar regions This is a phospholipid found in the plasma membranes of eukaryotic cells. It has a polar hydrophilic head group and a nonpolar hydrophobic tail group making it amphipathic. This chemical property allows it to form the lipid bilayer of the membrane with its polar group oriented on the surface of the membrane and its hydrophobic tails oriented away from the surrounding water in the interior of the lipid bilayer. - Nonpolar parts of phospholipids are fatty acid tail groups Which of the following is NOT true about phospholipids? a.) They contain a glycerol backbone. b) The head group is polar. c) The molecule is an important part of cell membranes. d) The tail groups are nonpolar. e) They are a major form of energy storage. 6. Enzymes and functions (catalyst) An Enzymes speeds up a chemical reaction without being altered or consumed. 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