Nokea
The bone cell type that breaks down the bone matrix is:
- A. Osteocytes
- B. Osteoclasts
- C. Osteoblasts
- D. Osteoprogenitor
Correct Answer: B
Rationale: The correct answer is B: Osteoclasts. Osteoclasts are bone cells responsible for breaking down the bone matrix through a process called bone resorption. They secrete enzymes and acids that dissolve the mineralized matrix, allowing for bone remodeling and repair. Osteocytes (A) are mature bone cells that help maintain bone tissue. Osteoblasts (C) are responsible for bone formation by synthesizing new bone matrix. Osteoprogenitor cells (D) are undifferentiated cells that can differentiate into osteoblasts. Therefore, the correct answer is B as osteoclasts specifically break down the bone matrix.
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A postpartum patient who has had a vaginal birth asks the nurse, I was wondering if my cervix will return to its previous shape before I had the baby? Which is the best response by the nurse?
- A. The cervix will now have a slit-like shap
- C. The cervix will be round and smooth after healing occurs.
- D. The cervix will remain 50% effaced now that you have had a baby.
Correct Answer: A
Rationale: The correct answer is A: The cervix will now have a slit-like shape. After giving birth, the cervix undergoes changes in shape and size to adapt to the delivery process. It becomes slit-like instead of round to allow for easier dilation in future pregnancies. This response is correct as it addresses the anatomical changes that occur postpartum.
Choice B is incorrect because it does not provide an explanation of the postpartum cervix shape changes.
Choice C is incorrect because it describes the cervix in a way that does not reflect the usual postpartum changes.
Choice D is incorrect because it refers to effacement, which is the thinning of the cervix during labor and not a permanent change postpartum.
Dichorionic-diamniotic twins result from separation of embryonic cells at the:
- A. Four-cell stage
- B. Blastocyst stage
- C. Implantation stage
- D. Trilaminar disc stage
Correct Answer: A
Rationale: The correct answer is A: Four-cell stage. Dichorionic-diamniotic twins occur when the embryo splits into two separate embryos very early in development, typically at the four-cell stage. At this stage, each embryo will have its own chorion and amnion, leading to separate placentas and amniotic sacs. Choices B, C, and D occur later in development and do not result in the formation of two separate embryos with their own chorion and amnion, making them incorrect for the scenario of dichorionic-diamniotic twins.
Which of the following structures is not involved with the development of the ova in the ovary?
- A. Corpus albicans
- B. Follicular cells
- C. Zona pellucida
- D. All of the above structures are involved in the development of the egg cell.
Correct Answer: A
Rationale: The corpus albicans is not involved in the development of ova.
In humans, the meiotic phase with the longest duration is:
- A. Anaphase I in males
- B. Prophase II in males
- C. Prophase I in females
- D. Anaphase II in females
Correct Answer: C
Rationale: The correct answer is C: Prophase I in females. Prophase I is the longest phase in meiosis due to the process of genetic recombination and crossing over. This phase involves pairing of homologous chromosomes, exchange of genetic material, and formation of chiasmata. These complex processes contribute to the extended duration of Prophase I.
Incorrect choices:
A: Anaphase I in males - Anaphase I is a relatively short phase where homologous chromosomes separate.
B: Prophase II in males - Prophase II is shorter than Prophase I as it involves the formation of new spindles and nuclear envelope breakdown.
D: Anaphase II in females - Anaphase II is also a short phase where sister chromatids separate.
A patient who experienced placenta previa is at increased risk of hemorrhage during the postpartal period because
- A. the placenta was smaller than normal
- B. the area of implantation does not contract effectively
- C. the placenta implanted very high in the uterus
Correct Answer: B
Rationale: Ineffective contraction of the placental site increases bleeding risk.