MYTUTOR SUBJECT ANSWERS

1592 views

Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline).

The heart muscle can contract by itself, without the stimulation of a nerve. This is called myogenic muscle contraction.

The region that initiates each contraction is found in the wall of the right atrium and is called the pacemaker. Every time the pacemaker sends out a signal, a heartbeat results. The pacemaker is under the influence of nerves (autonomic control from the brain, specifically the medulla oblongata (brain stem)) and adrenaline.

One nerve carries messages from the medulla of the brain to the pacemaker and speeds up the beating of the heart by releasing a neurotransmitter (noradrenaline) to increase the rate of myocardial contraction. Another nerve carries messages from the medulla of the brain to the pacemaker and slows down the beating of the heart by releasing a neurotransmitter (acetylcholine) to decrease the rate of myocardial contraction.

Additionally, the heart rate may be increased by the chemical release of the hormone adrenaline (epinephrine) into the blood (from the adrenal gland) and once it reaches the pacemaker it signals it to increase the beating of the heart.

 

Zana Katarina L. IB Biology tutor, IB Maths tutor, IB Psychology tutor

2 years ago

Answered by Zana Katarina, an IB Biology tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

20 SUBJECT SPECIALISTS

£22 /hr

Anna Liisa J.

Degree: Biomedical Science (Bachelors) - Kings, London University

Subjects offered:Biology, Economics+ 1 more

Biology
Economics
Chemistry

“My name is Anna Liisa Jalakas and I am a biomedical sciences student. I completed my IB diploma in June of 2016 where I achieved a total of 40 points with a 7 in Biology and Economics, and a 6 in Chemistry. I also have IGCSE qualifica...”

£24 /hr

Julia M.

Degree: Sustainable Agriculture and Food Security (Masters) - Edinburgh University

Subjects offered:Biology, Maths+ 1 more

Biology
Maths
Chemistry

“Enthusiastic friendly tutor looking for curious and ambitious students for fun and relaxed lessons”

£20 /hr

Adedayo S.

Degree: Medical Sciences (Bachelors) - Exeter University

Subjects offered:Biology, Spanish+ 1 more

Biology
Spanish
English Literature

“With tutoring, I share my passion for science and language. I'm excited to meet you and make you more than ready for what the exam may bring.”

MyTutor guarantee

About the author

£20 /hr

Zana Katarina L.

Degree: Psychology (Bachelors) - Durham University

Subjects offered:Biology, Psychology+ 1 more

Biology
Psychology
Maths

“Top tutor from the renowned Russell university group, ready to help you improve your grades.”

MyTutor guarantee

You may also like...

Posts by Zana Katarina

Describe one example of transient polymorphism.

Discuss the relative importance of genetic and cultural evolution in the recent evolution of humans.

Analyze the changes in concentration of atmospheric carbon dioxide using historical records.

Behaviour can be innate because it is genetically based and can be inherited.

Other IB Biology questions

Which protein structure is broken down due to denaturalization: primary, secondary, tertiary or quaternary?

Explain the process of synaptic transmission

State the source, substrate, products and optimum pH of one amylase, one protease, and one lipase

Explain the differences between primary, secondary and tertiary protein structure.

View IB Biology tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok