The Oestrus Cycle
The oestrus cycle, hormones of humans and animals - introductory vet
Questions and Answers
- 1.
What is the oestrus cycle?
- A.
A repetitive pattern of hormones and behaviour that leads to ovulation
- B.
A repetitive pattern of hormones that leads to ovulation
- C.
A repetitive pattern of behaviours that leads to ovulation
Correct Answer
A. A repetitive pattern of hormones and behaviour that leads to ovulationExplanation
The oestrus cycle refers to a repetitive pattern of hormones and behavior that leads to ovulation. This cycle involves hormonal changes in the body, which in turn affect the behavior of the individual. These changes prepare the body for potential fertilization and pregnancy. The behavior during this cycle can include increased sexual activity and receptivity to mating. Overall, the oestrus cycle is a complex process involving both hormonal and behavioral changes that ultimately result in ovulation.Rate this question:
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- 2.
Which of these are behavioural periods of oestrus?
- A.
Prooestrus
- B.
Oestrus
- C.
Metoestrus
- D.
Dioestrus
Correct Answer(s)
A. Prooestrus
B. OestrusExplanation
Prooestrus and oestrus are both behavioural periods of oestrus in animals. Prooestrus is the initial phase of the oestrus cycle, characterized by the preparation of the reproductive system for potential fertilization. Oestrus, on the other hand, is the period when the female is sexually receptive and actively seeks mating opportunities. Metoestrus and dioestrus are not behavioural periods of oestrus, but rather subsequent phases in the reproductive cycle.Rate this question:
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- 3.
Which of these are ecndocrine periods of oestrus?
- A.
Prooestrus
- B.
Oestrus
- C.
Metoestrus
- D.
Dioestrus
Correct Answer(s)
C. Metoestrus
D. DioestrusExplanation
Prooestrus and oestrus are not considered endocrine periods of oestrus, as they are stages within the estrous cycle. However, metoestrus and dioestrus are endocrine periods of oestrus. Metoestrus is the period following oestrus, characterized by the formation of the corpus luteum and increased progesterone levels. Dioestrus is the subsequent period, where progesterone levels remain high, preparing the uterus for potential pregnancy. These two stages play crucial roles in regulating the reproductive cycle in females.Rate this question:
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- 4.
Which of these make up the follicular stage?
- A.
Prooestrus
- B.
Oestrus
- C.
Metoestrus
- D.
Dioestrus
Correct Answer(s)
A. Prooestrus
B. OestrusExplanation
The follicular stage of the estrous cycle in animals consists of two phases: proestrus and estrus. Proestrus is the initial phase where the follicles in the ovaries start to develop and produce estrogen. This leads to the preparation of the uterus for potential pregnancy. Estrus is the second phase, also known as the "heat" phase, where the female is sexually receptive and ovulation occurs. Therefore, both proestrus and estrus are part of the follicular stage. Metoestrus and dioestrus, on the other hand, belong to the luteal stage of the estrous cycle.Rate this question:
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- 5.
Which of these make up the luteal stage?
- A.
Prooestrus
- B.
Oestrus
- C.
Metoestrus
- D.
Dioestrus
Correct Answer(s)
C. Metoestrus
D. DioestrusExplanation
The luteal stage of the estrous cycle in mammals consists of two phases: metoestrus and dioestrus. During metoestrus, the corpus luteum forms from the ruptured follicle after ovulation, and progesterone levels begin to rise. This phase prepares the uterus for potential pregnancy. Dioestrus follows metoestrus and is characterized by high levels of progesterone, which maintain the uterine lining and inhibit further follicular development. Together, metoestrus and dioestrus make up the luteal stage of the estrous cycle.Rate this question:
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- 6.
Proestrus is the formation of follicles, secretion of pheremones and the myometrium increases in size
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The ENDOmetrium increases in sizeRate this question:
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- 7.
The Follicular phase includes Proestrus and Oestrus and is Proliferative - the endometrium increases in size
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
In the follicular phase of the menstrual cycle, which includes Proestrus and Oestrus, the endometrium (the lining of the uterus) undergoes proliferation or growth. This is necessary to prepare the uterus for potential implantation of a fertilized egg. Therefore, the statement that the endometrium increases in size during the follicular phase is true.Rate this question:
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- 8.
The Luteal phase includes metoestrus and dioestrus and prepares for pregnancy and decides if it is pregnant. Lasts around 9-10 days in domestic speciese. It is the secretory phase as the endometrium begins to secrete progesterone
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Lasts 15-16 days in domestic species.Rate this question:
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- 9.
Which stage is when sexual receptitivty and ovulation occurs?
- A.
Proestrus
- B.
Oestrus
- C.
Metoestrus
- D.
Dioestrus
Correct Answer
B. OestrusExplanation
Oestrus is the stage when sexual receptivity and ovulation occur in female animals. During this stage, the female is ready to mate and can conceive. The hormones released during oestrus stimulate the development of the ovarian follicles, leading to ovulation. This stage is characterized by behavioral changes, such as increased vocalization and seeking out a mate. Therefore, oestrus is the correct answer because it specifically corresponds to the occurrence of sexual receptivity and ovulation.Rate this question:
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- 10.
Which stage is when formation of the corpus luteum and beginning of progesterone secretion occurs?
- A.
Proestrus
- B.
Oestrus
- C.
Metoestrus
- D.
Dioestrus
Correct Answer
C. MetoestrusExplanation
Metoestrus is the stage when the formation of the corpus luteum and the beginning of progesterone secretion occurs. During this stage, the follicle that released the egg during oestrus transforms into the corpus luteum, which produces progesterone. Progesterone is essential for maintaining pregnancy and preparing the uterus for implantation of a fertilized egg. Therefore, metoestrus is the correct answer for this question.Rate this question:
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- 11.
Which stage is when progesterone secretion continues?
- A.
Proestrus
- B.
Oestrus
- C.
Metoestrus
- D.
Dioestrus
Correct Answer
D. DioestrusExplanation
During the dioestrus stage, progesterone secretion continues. This stage occurs after the oestrus stage and is characterized by the development of the corpus luteum, which secretes progesterone. Progesterone is essential for maintaining pregnancy and preparing the uterus for implantation of a fertilized egg. It also inhibits the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), preventing the development of new follicles and ovulation. Therefore, the correct answer is Dioestrus.Rate this question:
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- 12.
What is polyoestrus
- A.
Continuous cycle of follicular, luteal, folliular
- B.
Continuous cycle of follicular, luteal, anoestrus, folliular
Correct Answer
A. Continuous cycle of follicular, luteal, folliularExplanation
Polyoestrus is a reproductive pattern in which female animals experience multiple estrous cycles throughout the year. This means that they have a continuous cycle of follicular development, followed by the formation of a corpus luteum during the luteal phase, and then another follicular development phase. This pattern allows for multiple opportunities for the female to become pregnant and reproduce throughout the year.Rate this question:
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- 13.
What animals are polyoestrus?
- A.
Human
- B.
Cow
- C.
Sow
- D.
Mare
- E.
Ewe
- F.
Dog
Correct Answer(s)
A. Human
B. Cow
C. SowExplanation
Polyoestrus refers to animals that have multiple estrous cycles throughout the year. This means that they can go into heat and reproduce multiple times within a year. Humans, cows, and sows are examples of polyoestrus animals. Humans have a menstrual cycle, cows have a estrous cycle, and sows have a heat cycle. This allows them to have the potential for multiple reproductive cycles in a year.Rate this question:
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- 14.
What animals are seasonal?
- A.
Doe
- B.
Cow
- C.
Queen
- D.
Mare
- E.
Ewe
- F.
Dog
Correct Answer(s)
A. Doe
C. Queen
D. Mare
E. EweExplanation
The animals mentioned in the answer (Doe, Queen, Mare, Ewe) are all female animals. Female animals have reproductive cycles that are often seasonal, meaning they only go into heat or are able to conceive during certain times of the year. This is in contrast to male animals, like cows and dogs, who are typically able to reproduce year-round. Therefore, the animals mentioned in the answer are considered seasonal in terms of their reproductive cycles.Rate this question:
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- 15.
What animals are monoestrus?
- A.
Doe
- B.
Cow
- C.
Fox
- D.
Mare
- E.
Ewe
- F.
Dog
Correct Answer(s)
C. Fox
F. DogExplanation
Fox and dog are the correct answers because they are both monoestrus animals. Monoestrus refers to animals that have only one estrous cycle per year. This means that they only go into heat and are fertile once a year. Other animals listed in the question such as doe, cow, mare, and ewe are polyestrus animals, which means they have multiple estrous cycles throughout the year.Rate this question:
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- 16.
Seasonal Oestrus is when repeated cycles are seen all year round
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Seen only at particular times (Horses, ewe, doe, queen)Rate this question:
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- 17.
Absence of Oestrus is called Anoestrus
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Anoestrus is indeed the term used to describe the absence of oestrus in animals. Oestrus refers to the recurring period of sexual receptivity and fertility in female mammals, commonly known as the heat cycle. Anoestrus occurs when this cycle is not present, which can happen naturally during certain periods or due to various factors such as pregnancy, lactation, or certain medical conditions. Therefore, the statement "Absence of Oestrus is called Anoestrus" is true.Rate this question:
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- 18.
Seasonal breeding is regulated by day length due to melatonin production from the pituitary gland which INHIBITS oestrus
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
From the PINEAL glandRate this question:
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- 19.
What animals are long day breeders?
- A.
Horse
- B.
Rabbit
- C.
Ewe
- D.
Human
Correct Answer(s)
A. Horse
B. RabbitExplanation
Come into season around April when day length increases and low levels of melatonin as it is secreted in the dark. Low levels mean it does not inhibit oestrus.Rate this question:
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- 20.
What animals are short day breeders?
- A.
Horse
- B.
Rabbit
- C.
Ewe
- D.
Human
Correct Answer
C. EweExplanation
Come into season around September when day length decreases and low levels of melatonin. Low levels mean it does not inhibit oestrus.Rate this question:
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- 21.
In the absence of pregnancy the Corpus Luteum must undergo Luteolysis before the next cycle can be initiaed - occurs through prostaglandin
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because in the absence of pregnancy, the corpus luteum (a temporary endocrine structure in the ovary) must undergo luteolysis (degeneration) before the next menstrual cycle can be initiated. This process is mediated by prostaglandins, which cause the regression of the corpus luteum and the subsequent shedding of the endometrial lining during menstruation.Rate this question:
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- 22.
What is Maternal Recognition?
- A.
A signal required to block prostaglandin (which causes lysis of CL) if pregnant
- B.
A signal required to secrete prostaglandin if pregnant
- C.
The body recognises if it is pregnant
Correct Answer
A. A signal required to block prostaglandin (which causes lysis of CL) if pregnantExplanation
Maternal recognition refers to a signal that is needed to block prostaglandin, which is responsible for the lysis or breakdown of the corpus luteum (CL), if the individual is pregnant. The CL is essential for maintaining pregnancy as it produces progesterone, which is necessary for the development of the uterine lining. By blocking prostaglandin, the CL is preserved, allowing it to continue producing progesterone and supporting the pregnancy. This signal is crucial in ensuring the successful continuation of pregnancy.Rate this question:
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- 23.
What hormone initiates Lactation?
- A.
Prolactin
- B.
FSH
- C.
Prostglandin
Correct Answer
A. ProlactinExplanation
Stimulated by suckling which stimulates afferent nerve causing prolactin and oxytocin secretion.Rate this question:
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