1.
Which one of the following cell types produces collagen, proteoglycans and glycosaminoglycans?
Correct Answer
D. Fibroblasts
Explanation
Fibroblasts are the correct answer because they are the main cell type responsible for producing collagen, proteoglycans, and glycosaminoglycans. Collagen is the main structural protein in the extracellular matrix, while proteoglycans and glycosaminoglycans are important components of the matrix that provide support and hydration to tissues. Fibroblasts are found in connective tissues throughout the body and play a crucial role in tissue repair and remodeling. They are able to synthesize and secrete these extracellular matrix components, making them essential for maintaining tissue structure and function.
2.
Which of the following statements concerning immediate
hypersensitivity reaction is CORRECT?
Correct Answer
C. IgE secreted from plasma cell binds to the IgE receptor of mast cells
Explanation
IgE is a type of antibody that is secreted from plasma cells. It binds to the IgE receptor on mast cells, triggering an immediate hypersensitivity reaction. This binding causes the mast cells to release various chemical mediators, such as histamine, which contribute to the allergic response. The other options mentioned in the question are not correct as they do not accurately describe the mechanisms involved in immediate hypersensitivity reactions.
3.
Which of the following statements regarding loose areolar
connective tissue is CORRECT?
Correct Answer
E. It has lots of ground substance, abundance of cell types and scattered fibers
Explanation
Loose areolar connective tissue is characterized by having lots of ground substance, an abundance of cell types, and scattered fibers. This tissue type provides support and flexibility to various organs and structures in the body. The presence of ground substance allows for the diffusion of nutrients and waste products, while the scattered fibers provide strength and support. The abundance of cell types, such as fibroblasts and immune cells, contributes to the tissue's ability to repair and defend against pathogens.
4.
Which of the following statements regarding collagen
biosynthesis is CORRECT?
Correct Answer
D. Vitamin C is essential for the hydroxylation of proline residues in the rough endoplasmic reticulum
Explanation
Vitamin C is required for the hydroxylation of proline residues in the rough endoplasmic reticulum. This hydroxylation step is important for the proper folding and stability of collagen molecules. Without vitamin C, the hydroxylation process is impaired, leading to the synthesis of structurally weak collagen. This is the main reason why vitamin C deficiency can result in a disease called scurvy, which is characterized by weakened connective tissues and impaired wound healing.
5.
Which of the following features regarding cartilage is CORRECT?
Correct Answer
B. Nutrients for chondrocytes of cartilage are derived from blood capillaries found in the perichondrium
Explanation
The correct answer is that nutrients for chondrocytes of cartilage are derived from blood capillaries found in the perichondrium. Chondrocytes are the cells that make up cartilage, and they require nutrients to survive and function properly. These nutrients are obtained from blood capillaries that are present in the perichondrium, which is the connective tissue that surrounds the cartilage. The perichondrium provides a source of oxygen and nutrients to the chondrocytes, allowing them to maintain their metabolic activities and support the health of the cartilage tissue.
6.
Which of the following processes is TRUE at the neuromuscular junction?
Correct Answer
E. Synaptic vesicles release acetylcholine into the synaptic cleft
Explanation
At the neuromuscular junction, synaptic vesicles release acetylcholine into the synaptic cleft. This is the correct process that occurs during the transmission of a nerve impulse from a motor neuron to a muscle cell. Acetylcholine is a neurotransmitter that is released from the synaptic vesicles and diffuses across the synaptic cleft to bind to receptors on the postsynaptic membrane of the muscle cell, initiating muscle contraction. The other options mentioned in the question are not accurate descriptions of the process at the neuromuscular junction.
7.
Which of the following statements during the time of menstruation is CORRECT?
Correct Answer
C. LH causes the final maturation of the Graafian follicle and release of the secondary oocyte
Explanation
During the time of menstruation, LH (luteinizing hormone) causes the final maturation of the Graafian follicle and the release of the secondary oocyte. This is a correct statement because LH surge triggers ovulation, which is the release of the mature egg from the ovary. The Graafian follicle, which contains the mature egg, ruptures and releases the secondary oocyte into the fallopian tube where it can potentially be fertilized by sperm.
8.
Which substance or hormone influences the endometrium during the
proliferative phase?
Correct Answer
E. Estrogen
Explanation
Estrogen is the correct answer because it is the hormone that primarily influences the endometrium during the proliferative phase. During this phase, the endometrium thickens and prepares for potential implantation of a fertilized egg. Estrogen stimulates the growth and development of the endometrial lining, ensuring it is ready to support a pregnancy if fertilization occurs. LH, FSH, Progesterone, and Activin also play important roles in the menstrual cycle, but they do not directly influence the endometrium during the proliferative phase.
9.
Which of the following statement is CORRECT regarding the
growing follicles before ovulation of the egg cell?
Correct Answer
C. FSH stimulates the granulosa layer of cells to secrete estrogen
Explanation
FSH (follicle-stimulating hormone) plays a crucial role in the development of the follicles before ovulation. It stimulates the granulosa layer of cells, which are located inside the follicles, to secrete estrogen. Estrogen is important for the growth and maturation of the follicles. It also helps in the development of the endometrium, the lining of the uterus, in preparation for potential implantation of a fertilized egg. Therefore, FSH's stimulation of the granulosa layer to produce estrogen is a correct statement regarding the growing follicles before ovulation.
10.
The inner mass of cells from the blastocyst stage of development
eventually gives rise to:
Correct Answer
D. Epiblast and hypoblast
Explanation
The inner mass of cells from the blastocyst stage of development eventually gives rise to the epiblast and hypoblast. These two cell layers are responsible for the formation of the embryo proper. The epiblast gives rise to the three primary germ layers (ectoderm, mesoderm, and endoderm), which go on to form all the tissues and organs of the body. The hypoblast, on the other hand, contributes to the formation of extra-embryonic structures like the yolk sac.
11.
Which of the following statements regarding fertilization is CORRECT?
Correct Answer
C. As soon as the sperm touches the oocyte plasma membrane, a zonal reaction takes place whereby the oocyte membrane and zona pellucida undergo a conformational change
Explanation
When a sperm touches the oocyte plasma membrane, a zonal reaction occurs. This reaction causes a conformational change in both the oocyte membrane and the zona pellucida. This change allows the sperm to penetrate the zona pellucida and reach the oocyte for fertilization. The statement correctly describes the process of fertilization and the role of the zonal reaction in allowing sperm entrance.
12.
Intraembryonic mesoderm is derived from the
Correct Answer
D. Epiblast
Explanation
The intraembryonic mesoderm is derived from the epiblast. During embryonic development, the epiblast differentiates into three germ layers: ectoderm, mesoderm, and endoderm. The mesoderm is located between the ectoderm and endoderm and gives rise to various structures such as muscles, bones, connective tissues, and cardiovascular system. Therefore, the correct answer is epiblast.
13.
Epiblast cells that enter the primitive node gives rise to:
Correct Answer
B. Notochordal rod that extends to the prochordal plate
Explanation
Epiblast cells that enter the primitive node give rise to the notochordal rod that extends to the prochordal plate. The notochordal rod is an essential structure in early embryonic development, providing structural support and signaling cues for the formation of the neural tube. It plays a crucial role in the formation of the axial skeleton and the development of the central nervous system. The prochordal plate is a specialized region of the endoderm that is involved in the formation of the oropharyngeal membrane.
14.
Which of the following structures is derived from ectoderm?
Correct Answer
B. Anterior pituitary gland
Explanation
The anterior pituitary gland is derived from the ectoderm. The ectoderm is one of the three primary germ layers that form during early embryonic development. It gives rise to various structures in the body, including the nervous system, skin, and some glands. The anterior pituitary gland is a major endocrine gland located in the brain that produces and releases several important hormones. Since it is derived from the ectoderm, it is the correct answer in this case.
15.
During meiosis, the secondary spermatocytes have
Correct Answer
B. 23 chromosomes
Explanation
During meiosis, the secondary spermatocytes have 23 chromosomes. Meiosis is the process of cell division that occurs in the reproductive cells to produce gametes (sperm or egg cells). It involves two rounds of division, resulting in four daughter cells with half the number of chromosomes as the parent cell. In humans, the parent cell (primary spermatocyte) has 46 chromosomes, and after the first division, the secondary spermatocytes are formed with 23 chromosomes. Therefore, the correct answer is 23 chromosomes.
16.
The posterior fontanelle is usually closed by
Correct Answer
B. Age 6 months
Explanation
The posterior fontanelle is a soft spot on the back of a baby's head where the skull bones have not yet fully fused. It is typically closed by the age of 6 months. During the first few months of life, the fontanelle allows for the baby's brain to grow and provides flexibility for the skull bones to shift during delivery. As the baby grows, the fontanelle gradually closes and becomes less noticeable. By the age of 6 months, it is expected that the posterior fontanelle will be fully closed.
17.
Which of the following statements is NOT considered to be significant to meiosis?
Correct Answer
D. Unequal cell size
Explanation
Unequal cell size is not considered to be significant to meiosis because it does not directly affect the process of genetic recombination or the separation of homologous chromosomes. Meiosis is primarily concerned with the exchange of genetic information through crossing over, the pairing of homologous chromosomes, and the independent assortment of maternal and paternal chromosomes. Unequal cell size may occur as a result of meiosis, but it is not a fundamental aspect of the process itself.
18.
At the time of birth in the XX individual, the gonad will contain
Correct Answer
D. Primordial follicles with primary oocytes of propHase I
Explanation
At the time of birth in an XX individual, the gonad will contain primordial follicles with primary oocytes of prophase I. This is because during fetal development, the oogonia (precursor cells) undergo mitotic divisions to form primary oocytes. These primary oocytes are arrested in prophase I of meiosis and are surrounded by a single layer of flattened cells, forming primordial follicles. These primordial follicles are present in the ovaries at birth and will eventually develop and mature during the reproductive years. Therefore, the presence of primordial follicles with primary oocytes of prophase I is the most appropriate answer.
19.
Which cell type produces the oocyte maturation inhibitory substance?
Correct Answer
C. Follicular cells of the primordial follicle
Explanation
Follicular cells of the primordial follicle produce the oocyte maturation inhibitory substance. These cells surround the developing oocyte and play a crucial role in its maturation process. They release various substances, including the oocyte maturation inhibitory substance, which helps regulate the timing of oocyte maturation and prevents premature maturation. This substance ensures that the oocyte is fully developed and ready for fertilization before it is released from the ovary during ovulation.
20.
If the secondary oocyte is ferti1ized
Correct Answer
B. Human chorionic gonadotropin produced by the syncytiotropHoblast cells maintains the viability of the corpus luteum
Explanation
After the secondary oocyte is fertilized, the syncytiotrophoblast cells in the developing embryo produce human chorionic gonadotropin (hCG). This hormone maintains the viability of the corpus luteum, preventing it from degenerating. The corpus luteum is responsible for producing progesterone, which is essential for maintaining the pregnancy. If the corpus luteum degenerates, progesterone levels drop and the uterine lining is shed, resulting in menstruation. Therefore, the production of hCG by the syncytiotrophoblast cells ensures the survival of the corpus luteum and the maintenance of the pregnancy.
21.
Which of the following statements concerning fertilization is NOT CORRECT?
Correct Answer
D. The zonal reaction allows other sperms to penetrate the oocyte
Explanation
The zonal reaction does not allow other sperms to penetrate the oocyte. Instead, it prevents additional sperms from entering the oocyte by causing the zona pellucida to harden and become impenetrable.
22.
Which of the following features regarding the second week of development is CORRECT?
Correct Answer
B. SyncytiotropHoblast cells are involved in eroding maternal sinusoids to establish the primitive uteroplacental circulation
Explanation
Syncytiotrophoblast cells are involved in eroding maternal sinusoids to establish the primitive uteroplacental circulation. During the second week of development, the syncytiotrophoblast cells invade the maternal sinusoids in the endometrium, allowing for the establishment of the primitive uteroplacental circulation. This process is crucial for the exchange of nutrients and waste between the maternal and embryonic circulations. The other options are not correct because lacunae spaces are formed in the extraembryonic mesoderm, epiblast cells are not involved in establishing the uteroplacental circulation, the cytotrophoblast layer does not erode the maternal endometrium, and the hypoblast layer does not give rise to the amnion.
23.
During the second week of development, the embryo proper is composed of
Correct Answer
B. Epiblast and hypoblast
Explanation
During the second week of development, the embryo proper is composed of epiblast and hypoblast. These two layers are part of the inner cell mass, which is formed after the blastocyst stage. The epiblast is the upper layer and gives rise to the three primary germ layers, which eventually develop into all the tissues and organs of the body. The hypoblast is the lower layer and contributes to the formation of extraembryonic structures like the yolk sac. Together, the epiblast and hypoblast play crucial roles in the early development of the embryo.
24.
The prochordal plate is a group of tall columnar cells that
Correct Answer
C. Determine the future site of the mouth cavity
Explanation
The prochordal plate is a group of tall columnar cells that determine the future site of the mouth cavity. This means that during development, the prochordal plate plays a crucial role in establishing where the mouth will be located in the embryo. It provides important signals and cues for the formation and positioning of the mouth structures.
25.
During the female reproductive cycle
Correct Answer
A. LH stimulates the formation of the corpus luteum
Explanation
LH, or luteinizing hormone, stimulates the formation of the corpus luteum. The corpus luteum is a temporary endocrine structure that develops from the ruptured ovarian follicle after ovulation. It secretes progesterone, which is important for preparing the uterus for potential implantation of a fertilized egg. LH triggers the transformation of the follicle into the corpus luteum, ensuring the production of progesterone and supporting the early stages of pregnancy if fertilization occurs.
26.
At the time of ovulation
Correct Answer
A. The released egg is a secondary oocyte arrested at metapHase II of meiosis II
Explanation
The correct answer is that the released egg is a secondary oocyte arrested at metaphase II of meiosis II. During ovulation, the secondary oocyte is released from the ovary. It is in the metaphase II stage of meiosis II, which means it has already gone through the first meiotic division and is ready to be fertilized by a sperm. If fertilization occurs, the secondary oocyte will complete meiosis II and become a mature egg. If fertilization does not occur, the secondary oocyte will degenerate.
27.
Which of the following, statements concerning simple columnar epithelium is NOT CORRECT?
Correct Answer
C. It is found lining the epididymis
Explanation
slide 24 and 25
28.
Hemidesmosomes are
Correct Answer
E. Composed in part of actin microfilaments
Explanation
ANSWER KEY SHOWS E AS CORRECT ANSWER BUT SLIDE 50 AND 51 MAKE C ALSO A GOOD ANSWER . THEREFORE THIS IS A STUPID QUESTION.
29.
Which of the following statements regarding stratified squamous keratinized epithelium is NOT CORRECT?
Correct Answer
E. Blood vessels penetrate this epithelium
Explanation
Stratified squamous keratinized epithelium is avascular, meaning it does not have blood vessels. The other statements are correct - it is found covering the surface of the skin, the basal layer of cells may be cuboidal or columnar and rest on the basal lamina, some of its cells rest on the basal lamina, and the apical cells are squamous and dead.
30.
Which of the following statements concerning classification of exocrine glands is NOT CORRECT?
Correct Answer
D. The shape of the secretory unit may be mucous
Explanation
Classification of exocrine glands –based on :
1. Nature of cells – (unicellular versus multicellular)
2. Nature of duct system – (simple vs compound )
3. Shape of secretion unit – (tubular vs alveolar (acini)
vs tubuloalveolar )
4. Nature of secretion product – (mucus vs serous vs seromucus)
5. Mode of secretion – (holocrine vs merocrine vs apocrine )
from slide #52