Bioscience 1 Assessment 2 (Part B): Cardiac Conduction & Vitamin B12

This Bioscience 1 Assessment 2 (Part B) assignment, completed by a student, addresses the cardiac conduction system and the role of vitamin B12. The assignment begins with a feedback review of Part A, emphasizing the importance of referencing and paraphrasing, and includes questions about in-text citations, reference lists, and Turnitin similarity percentages. The short answer questions delve into the components and conduction pathway of the heart's cardiac conduction system, relating it to the sequence of heart chamber contractions. Additionally, the assignment explores vitamin B12, covering food sources, functions in the body, consequences of deficiency in pregnant and non-pregnant individuals, and risk groups for deficiency. The assignment adheres to APA referencing style, with a reference list provided.

Bioscience 1 Assessment 2 (Part B)
Do NOT delete any part of the template
Due Monday 6th May 2019, midnight
Student Name:
Student ID:
Task 1- Feedback review on Part A
This activity is to be completed and submitted as part of Assessment 2 (Part B).
This activity should bring to your attention the importance of referencing and
paraphrasing and help to improve your marks awarded for Academic Style and
Referencing.
Use your submitted Assessment 2 (Part A) when considering the following
questions. Please highlight or underline your chosen answer.
a) Did you include in-text references in your answer and a reference list at the end?
a) Yes
b) No
b) What is the purpose of including in-text references and a reference list in an
assessment?
a) Provide evidence for the source of the information
b) Allows information to be included without paraphrasing
c) Permits information to be directly copied without rewriting
c) What is the purpose of submitting your assessment through Turnitin?
a) Allows you to identify material that needs to be referenced
b) Allows you to identify material that needs to be paraphrased
c) Allows you to identify incorrect information that should be removed
d) Which of the following Turnitin similarity percentages best represents an
assessment that has been well paraphrased?
a) 80-95%
b) 50-60%
c) 10-30%
Make sure you include in-text references in every answer and check your Turnitin
similarity % at least three days before the due date so you have time to paraphrase
your answers.

Bioscience 1 Assessment 2 (Part B)
Task 2- Short answer questions.
Note: Answers must be in complete sentences and include in-text references
Answer the following questions:
Question 2-
Describe the components and conduction pathway of the cardiac conduction
system of the heart. (200 words, 5 marks)
Answer:
Cardiac conduction system usually is defined as a specialised group consisting of
cells of the muscles present in the heart walls. This conduction system plays the function
of sending signals to heart muscles which ultimately cause contraction. The main
components inclusive of conduction system are SA nodes, AV nodes, Purkinje fibres
bundle of His.
The conduction of electrical impulses starts with the SA node which is also known
as the pacemaker. They play an important role of starting the whole sequence thereby
leading to the contraction of the atrial muscles. After SA nodal excitation, depolarization
spreads to atria and the signal travels to the AV nodes next which further travels through
the component known as the bundle of His. Then the wave of cardiac depolarization
ultimately distributes to the left and right bundle branches and finally causes ventricular
contraction. This network of the bundle branches is very complex and is made of various
rapid conducting cells which are known as Purkinje fibres. Thus, there is an electrical
current which is created and can usually be seen on graphs known as the
electrocardiogram. ECG is used for monitoring the conduction system of the heart
through measurement of its electrical activity (Sharawi, 2015).

Bioscience 1 Assessment 2 (Part B)
Relate the conduction system to the corresponding sequence of heart chamber
contractions. (200 words, 5 marks)
Answer:
Firstly the electrical signals which arise in the Sino-atrial (SA) node is in the right
atrium and it simultaneously causes atrial contraction. The various anterior internodal
pathways start with the anterior margin of SA and it usually curves around for entering
the anterior inter-atrial band. The presence of the Bachman bundle helps in the
conduction of impulse from the left atrium to the right atrium causing atrial contraction.
Thus the generation of the action potential by the SA node is the main cause for the atrial
contraction. The signal travelling to the AV nodes is situated in inter- atrial septum. Then
there is divergence of the signal followed by the conduction through left and right bundle
of His further being carried to the Purkinje fibres which ultimately cause ventricular
contraction. There is a constant pattern of spontaneous de-polarization which is usually
followed by repolarization. The right ventricle is de-polarized by the right bundle branch
while the left ventricle is depolarized by the left bundle branch. This fluctuating difference
in action potentials followed by regular intervals of de-polarization ultimately leads to
ventricular contractions. Thus if considered on a microscopic level waves of
depolarization propagates via gap junctions leading to a functional syncytium (Weerd &
Christophels, 2016).
Question 3- Vitamin B12 is an essential nutrient that is important for normal
development and health. Please answer the following:

Bioscience 1 Assessment 2 (Part B)
a) Name two food sources high in vitamin B12 (20 words; 0.5 mark)
Answer:
Two food sources which are high in amounts of Vitamin B12 are fish and red meat
(Watanabe et al., 2014).
b) Describe the functions of vitamin B12 in the body (60 words; 1.5 marks)
Answer:
Vitamin B 12 is an important nutrient for maintenance of the nerve as well
as blood cells. Being a water soluble vitamin it easily travels through bloodstream.
It helps in the production of DNA in the body. It also helps in the prevention of
disease known as megaloblastic anaemia which would be instrumental in fatigue,
weakness in people (Kennedy, 2016).
c) Describe the possible consequences to the body if there is a deficiency in
vitamin B12 in pregnant and non-pregnant individuals (80 words; 2 marks)
Answer:
Vitamin B 12 usually crosses the placenta during pregnancy. It is important
component of breast milk. Thus breastfed infants where there is limited supply of
Vitamin B12 in pregnant women can develop deficiency causing severe cases of
permanent damage to neurological system.

Bioscience 1 Assessment 2 (Part B)
Non pregnant women due to deficiency in Vitamin B 12 suffer from
symptoms like fatigue, smooth tongue, nerve problems like muscle weakness and
motility problems. They also suffer from constipation, paleness in the skin and loss
of appetite (Pawlak, Lester & Babatunde, 2014).
d) Name one group of people that is more likely to be at risk of becoming
deficient in vitamin B12 and why. (40 words; 1 mark)
Answer:
The target group for Vitamin B12 deficiency are usually older people as
natural intake of Vitamin B12 is not sufficient to meet the needs at an older age
and dietary supplements are not taken thus causing them to be vulnerable (Wong,
2015).

Bioscience 1 Assessment 2 (Part B)
References
Kennedy, D. (2016). B vitamins and the brain: Mechanisms, dose and efficacy—A
review. Nutrients, 8(2), 68.
Pawlak, R., Lester, S. E., & Babatunde, T. (2014). The prevalence of cobalamin
deficiency among vegetarians assessed by serum vitamin B12: a review of
literature. European journal of clinical nutrition, 68(5), 541.
Sharawi, M. A. M. (2015). Evaluation of Heart Stroke Volume Using single Photon
Emission Computed Tomography(Doctoral dissertation, Sudan University of
Science and Technology).
van Weerd, J. H., & Christoffels, V. M. (2016). The formation and function of the cardiac
conduction system. Development, 143(2), 197-210.
Watanabe, F., Yabuta, Y., Bito, T., & Teng, F. (2014). Vitamin B12-containing plant food
sources for vegetarians. Nutrients, 6(5), 1861-1873.
Wong, C. W. (2015). Vitamin B12 deficiency in the elderly: is it worth screening. Hong
Kong Med J, 21(2), 155-64.