Which of the following layers of skin lack blood vessels?
A. Papillary
B. Epidermis
C. Reticular
D. Hypodermis
The layer of skin that lacks blood vessels is the epidermis. The epidermis is the thin outer layer of the skin and does not have any blood vessels within it. It is composed of keratinized, stratified squamous epithelium and is made of four or five layers of epithelial cells, depending on its location in the body.
The other options are not correct because they do contain blood vessels. The papillary layer is part of the dermis, which contains blood vessels. The reticular layer is also part of the dermis and contains blood vessels . The hypodermis is a layer below the dermis and also contains blood vessels.
Therefore, the Correct Answer is B.
More Questions on TEAS 7 Science
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Q #1: The mitochondrial inner membrane carries out the same function in cellular respiration as the ________ membrane of chloroplasts in photosynthesis. Which of the following correctly completes the sentence above?
A. Thylakoid
B. Epithelial
C. Nuclear
D. Tonoplast
Answer Explanation
The thylakoid membrane of chloroplasts is where the light-dependent reactions of photosynthesis take place, while the mitochondrial inner membrane is where the electron transport chain and ATP synthesis occur during cellular respiration.
The tonoplast is the membrane that surrounds the central vacuole in plant cells. It is not involved in cellular respiration or photosynthesis.
The other options, epithelial and nuclear, are not related to these processes.
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Q #2: Which of the following functions does the myelin sheath perform for a nerve cell?
A. Insulation
B. Regeneration
C. Sensory perception
D. Nutrition
Answer Explanation
The myelin sheath is a protective membrane that wraps around parts of certain nerve cells.
Its fatty-protein coating provides protective insulation for your nerve cell like the plastic insulation covering that encases the wires of an electrical cord ².
This allows the electrical impulses to travel quickly and efficiently between one nerve cell and the next. The other options are incorrect because they do not describe the functions of the myelin sheath.
Regeneration, sensory perception, and nutrition are not functions performed by the myelin sheath for a nerve cell.
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Q #3: Which of the following terms describes the relaxation of the chambers of the heart during the cardiac cycle?
A. Tachycardia
B. Diastole
C. Systole
D. Bradycardia
Answer Explanation
The relaxation of the chambers of the heart during the cardiac cycle is called diastole ¹. The cardiac cycle is a sequence of events that occurs when the heart beats ². It consists of two phases: systole, when the heart contracts and pumps blood into circulation, and diastole, when the heart relaxes and fills with blood ².
The other options are not correct because they do not accurately describe the relaxation of the chambers of the heart during the cardiac cycle. Tachycardia is a rapid heart rate, bradycardia is a slow heart rate, and systole is the contraction of the heart chambers.
