smc-3647-50-Hormones

BIOLOGY, M5 2023 HSC 23

The following graph outlines some hormonal changes during pregnancy.

Complete the table for TWO of the hormones graphed. (4 marks)

\begin{array} {|c|c|c|}
\hline
\rule{0pt}{2.5ex} \quad \textit{Hormone name} \quad \rule[-1ex]{0pt}{0pt} & \quad \quad \textit{Function in pregnancy} \quad \quad & \quad \textit{Trimester where}\quad \\
\text{} \rule[-1.5ex]{0pt}{0pt} & \text{} & \textit{peak occurs}\\
\hline
\text{} & \text{} & \text{} \\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{} \\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\hline
\text{} & \text{} & \text{} \\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{} \\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\text{} & \text{} & \text{}\\
\hline
\end{array}

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Answers could include two of the following:

Hormone Name	Function in Pregnancy	Trimester where Peak Occurs
Progesterone	Initially, progesterone thickens the uterine lining to support the developing foetus. It is also produced in the placenta, helping to prevent lactation and contractions until full development.	It will slowly increase until a peak in the third trimester when the placenta is fully developed.
Oestrogen	Oestrogen is needed for stimulation of the development of the placenta, increasing the size of the uterus and helping the development of foetal organs.	Oestrogen will also gradually increase over time and peak in the final trimester.
Human Chorionic Gonadotrophin (hCG)	As soon as the blastocyst is implanted in the body, hCG will keep the corpus luteum active so it can produce oestrogen and progesterone.	hCG will peak in the first trimester.

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Answers could include two of the following:

Hormone Name	Function in Pregnancy	Trimester where Peak Occurs
Progesterone	Initially, progesterone thickens the uterine lining to support the developing foetus. It is also produced in the placenta, helping to prevent lactation and contractions until full development.	It will slowly increase until a peak in the third trimester when the placenta is fully developed.
Oestrogen	Oestrogen is needed for stimulation of the development of the placenta, increasing the size of the uterus and helping the development of foetal organs.	Oestrogen will also gradually increase over time and peak in the final trimester.
Human Chorionic Gonadotrophin (hCG)	As soon as the blastocyst is implanted in the body, hCG will keep the corpus luteum active so it can produce oestrogen and progesterone.	hCG will peak in the first trimester.

BIOLOGY, M5 EQ-Bank 22

The following data shows the average amount of Human Chorionic Gonadotropin (hCG) produced by pregnant women.

\begin{array}{|c|c|}
\hline \rule{0pt}{2.5ex}\text {Weeks of pregnancy} \rule[-1ex]{0pt}{0pt} & h C G\,\text{(ng/mL)} \\
\hline \rule{0pt}{2.5ex}0 \rule[-1ex]{0pt}{0pt}& 0 \\
\hline \rule{0pt}{2.5ex}4 \rule[-1ex]{0pt}{0pt}& 85 \\
\hline \rule{0pt}{2.5ex}8 \rule[-1ex]{0pt}{0pt}& 185 \\
\hline \rule{0pt}{2.5ex}12 \rule[-1ex]{0pt}{0pt}& 185 \\
\hline \rule{0pt}{2.5ex}16 \rule[-1ex]{0pt}{0pt}& 80 \\
\hline \rule{0pt}{2.5ex}20 \rule[-1ex]{0pt}{0pt}& 65 \\
\hline \rule{0pt}{2.5ex}24 \rule[-1ex]{0pt}{0pt}& 60 \\
\hline \rule{0pt}{2.5ex}28 \rule[-1ex]{0pt}{0pt}& 65 \\
\hline \rule{0pt}{2.5ex}32 \rule[-1ex]{0pt}{0pt}& 75 \\
\hline \rule{0pt}{2.5ex}36 \rule[-1ex]{0pt}{0pt}& 65 \\
\hline \rule{0pt}{2.5ex}40 \rule[-1ex]{0pt}{0pt}& 35 \\
\hline
\end{array}

Use the information provided to graph the levels of hCG in a normal pregnancy. (3 marks)
Describe the role and changes in levels of a hormone in pregnancy. (3 marks)

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b. The role and changes in levels of hormones in pregnancy.

→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.

→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.

→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.

Answers could also include information about other hormones including

→ Oestrogen

→ hCG

Show Worked Solution

b. The role and changes in levels of hormones in pregnancy.

→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.

→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.

→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.

Answers could also include information about other hormones including

→ Oestrogen

→ hCG

BIOLOGY, M5 2019 HSC 18 MC

The diagram shows the effect of the hormone oxytocin on the uterus during the birth of a mammal.

Which of the following best identifies and explains the feedback loop demonstrated in the diagram?

\begin{align*}
\begin{array}{l}
\ & \\
\rule{0pt}{3.5 ex}\textbf{A.}\\
\\
\textbf{B.}\\
\\
\textbf{C.}\\
\\
\textbf{D.}\\
\\
\end{array}
\begin{array}{|l|l|}
\hline
\rule{0pt}{2.5ex}\textit{Feedback loop} \rule[-1ex]{0pt}{0pt} & \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \textit{Explanation} \\
\hline
\text{Negative} & \text{The production of oxytocin results in the production of more} \\
\text{} & \text{oxytocin.} \\
\hline
\text{Positive} & \text{The production of oxytocin results in the production of more} \\
\text{} & \text{oxytocin.} \\
\hline
\text{Negative} & \text{The production of oxytocin results in the detection of the} \\
\text{} & \text{contraction by receptors in the cervix.} \\
\hline
\text{Positive} & \text{The production of oxytocin results in the detection of the} \\
\text{} & \text{contraction by receptors in the cervix.} \\
\hline
\end{array}
\end{align*}

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\(B\)

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→ Oxytocin is a chemical which maintains cervical contractions by releasing more oxytocin when the cervix is contracted, a property of a positive feedback mechanism.

\(\Rightarrow B\)

♦♦ Mean mark 31%.

BIOLOGY, M5 2021 HSC 23

Ovulation in women is associated with a rapid increase in luteinising hormone (LH). Test strips can be used to detect high levels of LH in urine. Once a test strip is used, a control line should appear and the presence of a test line indicates high levels of LH in urine. The image below represents four different results that were obtained.

Which of the results indicates a valid test which shows that ovulation is NOT occurring? Justify your answer. (3 marks)

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→ Test strips 3 and 4 do not contain a control line, therefore are invalid.

→ Test strip 2 contains a control line but no test line, indicating that there was no LH surge.

→ Therefore, test strip 2 indicates a valid negative result that shows ovulation is not occurring.

Show Worked Solution

→ Test strips 3 and 4 do not contain a control line, therefore are invalid.

→ Test strip 2 contains a control line but no test line, indicating that there was no LH surge.

→ Therefore, test strip 2 indicates a valid negative result that shows ovulation is not occurring.

BIOLOGY, M5 2021 HSC 12 MC

The graph shows the levels of three hormones, oestrogen, progesterone and human chorionic gonadotrophin (HCG), measured in the blood of a woman during her pregnancy.

Which statement can be inferred from the graph?

Birth occurred about week 36.
Fertilisation occurred at day 0.
Implantation occurred about week 4.
The placenta was formed about week 24.

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`C`

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→ HCG is released once the embryo has implanted.

→ Implantation occurs approximately 5-6 days after fertilisation which can take place when ovulation occurs, approximately 2 weeks after the menstrual cycle ends.

`=>C`

♦ Mean mark 49%.