While hiking, a person is startled after encountering a bear. Her palms get sweaty and her heart starts racing. Which part of her nervous system was directly stimulated?
A. Central
B. Parasympathetic
C. Somatic
D. Sympathetic
The autonomic nervous system is responsible for activities that are nonvoluntary and under unconscious control. This system controls glands and the smooth muscles of internal organs, heart rate, breathing, and digestion. The autonomic nervous system is further divided into the following:
- Sympathetic nervous system: The sympathetic nervous system focuses on emergency situations by preparing the body for fight or flight. (Sympathetic = Stress)
- Parasympathetic nervous system: The parasympathetic nervous system controls involuntary processes unrelated to emergencies. This system deals with “rest or digest” activities. (Parasympathetic = Peace)
The somatic nervous system primarily controls voluntary activities such as walking and riding a bicycle. Thus, this system sends information to the CNS and motor nerve fibers that are attached to skeletal muscle.
Therefore, the Correct Answer is D.
More Questions on TEAS 7 Science
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Q #1: What type of reaction is described by the following equation? ZnBr2(aq) + 2KOH(aq) → Zn(OH)2(s) + 2KBr(aq)
A. Synthesis
B. Decomposition
C. Single-Replacement
D. Double-Replacement
Answer Explanation
In this reaction, two elements are trading places hence double-replacement. In the reactants, zinc and bromide ions are together, and potassium and hydroxide ions are together. In the products, zinc and hydroxide ions are together, and potassium and bromide ions are together.
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Q #2: In the following single-replacement reaction, ______ replaces ______. Cl2+2NaI→2NaCl+I2
A. sodium, iodine
B. chlorine, iodine
C. chlorine, sodium
D. sodium, chlorine
Answer Explanation
In this reaction, chlorine (Cl2) is an element in the reaction that replaces iodine in the compound sodium iodide (NaI). This allows chlorine to form a compound with sodium (NaCl) and leaves iodine (I2) as an element.
Synthesis reactions involve two or more reactants (A and B) combining to form one product (AB). In the example provided, hydrogen (H2) and oxygen (O2) begin as separate elements. At the end of the reaction, the hydrogen and oxygen atoms are bonded in a molecule of water (H2O).
Decomposition reactions have only one reactant (AB) that breaks apart into two or more products (A and B). In the example above, hydrogen peroxide (H2O2) breaks apart into two smaller molecules: water (H2O) and oxygen (O2).
Single-replacement reactions involve two reactants, one compound (AB) and one element (C). In this type of reaction, one element replaces another to form a new compound (AC), leaving one element by itself (B). In the example, zinc replaces hydrogen in hydrochloric acid (HCl). As a result, zinc forms a compound with chlorine, zinc chloride (ZnCl2), and hydrogen (H2) is left by itself.
Double-replacement reactions involve two reactants, both of which are compounds made of two components (AB and CD). In the example, silver nitrate, composed of silver (Ag1+) and nitrate (NO31-) ions, reacts with sodium chloride, composed of sodium (Na1+) and chloride (Cl1-) ions. The nitrate and chloride ions switch places to produce two compounds that are different from those in the reactants.
Combustion reactions occur when fuels burn, and they involve specific reactants and products, as seen in the examples below. Some form of fuel that contains carbon and hydrogen is required. Examples of such fuels are methane, propane in a gas grill, butane in a lighter, and octane in gasoline. Notice that these fuels all react with oxygen, which is necessary for anything to burn. In all combustion reactions, carbon dioxide, water, and energy are produced. When something burns, energy is released, which can be felt as heat and seen as light.
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Q #3: What organelle is only associated with plant cells?
A. Cell wall
B. Ribosome
C. Cytoplasm
D. Golgi apparatus
Answer Explanation
Only plant cells have cell walls, which help protect the cell and provide structural support. The cell wall also enforces the overall structural integrity of the plant cell, and it is found outside the cell membrane. The next organelle is a chloroplast. It is found in the cytoplasm of only plant cells. Chloroplasts are photosynthetic compounds used to make food for plant cells by harnessing energy from the sun. These organelles play a role in photosynthesis.
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Q #4: During which of the following phase changes will the cohesion between the particles in a substance decrease?
A. Condensation
B. Deposition
C. Freezing
D. Vaporization
Answer Explanation
If the cohesion between particles decreases, then the particles must be undergoing a phase change that allows particles to move farther apart. This happens when a substance vaporizes and turns from liquid to gas. Any phase change that moves to the right in the diagram above requires energy to be added to the system because the substance has more energy at the end of the phase change. The phase changes are melting, vaporization (boiling), and sublimation. When energy is added, particles move faster and can break away from each other more easily as they move to a state of matter with a higher amount of energy. This is most commonly done by heating the substance.
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Q #5: What is the correct order of the stages of the cell cycle?
A. G1,S,G2,M
B. G2,S,G1,M
C. M,S,G2,G1
D. S,M,G1,G1
Answer Explanation
The cell cycle is an organized process divided into two phases: interphase and the M (mitotic) phase. During interphase, the cell grows and copies its DNA. After the cell reaches the M phase, division of the two new cells can occur. The G1, S, and G2 phases make up interphase.
- G1: The first gap phase, during which the cell prepares to copy its DNA
- S: The synthesis phase, during which DNA is copied
- G2 : The second gap phase, during which the cell prepares for cell division
It may appear that little is happening in the cell during the gap phases. Most of the activity occurs at the level of enzymes and macromolecules. The cell produces things like nucleotides for synthesizing new DNA strands, enzymes for copying the DNA, and tubulin proteins for building the mitotic spindle. During the S phase, the DNA in the cell doubles, but few other signs are obvious under the microscope. All the dramatic events that can be seen under a microscope occur during the M phase: the chromosomes move, and the cell splits into two new cells with identical nuclei.
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Q #6: Which choice best describes homeostasis?
A. A functional system of the body
B. Blood flow to every cell in the body
C. A relatively constant environment within the body
D. Neural pathways that have integrated into the body
Answer Explanation
Homeostasis is the existence and maintenance of a relatively constant environment within the body. Each cell of the body is surrounded by a small amount of fluid, and the normal functions of each cell depend on the maintenance of its fluid environment within a narrow range of conditions, including temperature, volume, and chemical content. These conditions are known as variables. For example, body temperature is a variable that can increase in a hot environment or decrease in a cold environment.
There are two types of feedback mechanisms in the human body: negative and positive.
- Negative Feedback: Most systems of the body are regulated by negative feedback mechanisms, which maintain homeostasis. Negative means that any deviation from the set point is made smaller or is resisted. The maintenance of normal blood pressure is a negative-feedback mechanism. Normal blood pressure is important because it is responsible for moving blood from the heart to tissues.
- Positive Feedback: Positive-feedback mechanisms are not homeostatic and are rare in healthy individuals. Positive means that when a deviation from a normal value occurs, the response of the system is to make the deviation even greater. Positive feedback therefore usually creates a cycle leading away from homeostasis and, in some cases, results in death. Inadequate delivery of blood to cardiac muscle is an example of positive feedback.
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Q #7: If a person smells something sweet, what form of information is this initially perceived as in the nervous system?
A. Cognitive
B. Integrative
C. Motor
D. Sensory
Answer Explanation
A sensory nerve is a nerve that carries sensory signals from the external environment to the brain to the central nervous system. It is also an afferent nerve, long dendrites of sensory neurons, which sends sensory information towards the central nervous system (CNS). This information is what is sensed, using the five senses from external environment, sight, sound, smell, taste, and touch.
Motor nerves have only efferent fibers, long axons of motor neurons, that carry impulses away from the CNS to the effectors, which are typically tissues and muscles of the body.
Interneurons are nerve cells that act as a bridge between motor and sensory neurons in the CNS. These neurons help form neural circuits, which helps neurons communicate with each other.
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Q #8: In which state of matter are the intermolecular forces between particles in a substance the strongest?
A. Gas
B. Liquid
C. Plasma
D. Solid
Answer Explanation
In solids, particles are usually closer together than in other states of matter because of the strong cohesive forces between the particles.
- Solids, liquids, gases, and plasmas differ from one another in the amount of energy that the particles have and the strength of the cohesive forces that hold the particles together.
- Cohesion is the tendency of particles of the same kind to stick to each other.
- A solid has the lowest amount of energy because its particles are packed close together. Liquids have more energy than a solid, and gases have more energy than solids or liquids because the cohesive forces are very weak.
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Q #9: A student notices a pattern of stripes on five tigers. Each of the five tigers has the same stripe pattern. Using his inductive reasoning, what does he logically assume based on this information?
A. The pattern continues to change over time.
B. Natural adaptations cause this pattern to occur
C. Each offspring will have the same stripe pattern
D. Ancestors of the tigers have different stripe patterns
Answer Explanation
Inductive reasoning involves making specific observations and using them to make broad statements. The student observes that all of the tigers have the same stripe pattern. He can use this observation to make the broad statement that all the tigers’ offspring will have the same stripe pattern.
Inductive reasoning involves drawing a general conclusion from specific observations. This form of reasoning is referred to as the “from the bottom up” approach. Information gathered from specific observations can be used to make a general conclusion about the topic under investigation. In other words, conclusions are based on observed patterns in data.
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Q #10: What is the final structure through which urine must travel to empty out of the body?
A. Bladder
B. Kidney
C. Ureter
D. Urethra
Answer Explanation
The primary organ of the urinary system is the kidney. Blood from the heart flows through the kidneys via the renal artery. As blood drains from the kidney, it exits through a series of veins, the most prominent of which is the renal vein. When urine is produced, it does not drain through the tubes through which blood flows. Rather, urine flows through two ureters before emptying into the urinary bladder.
The following steps outline how the urinary system works:
- Kidney filters and excretes wastes from blood, producing urine.
- Urine flows down the ureters.
- Urine empties into the bladder and is temporarily stored.
- Bladder, when filled, empties urine out of the body via the urethra.
