MYTUTOR SUBJECT ANSWERS

905 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

22 SUBJECT SPECIALISTS

£20 /hr

Victoria T.

Degree: Biomedical Sciences (Bachelors) - Queen Mary, London University

Subjects offered: Biology, Japanese+ 1 more

Biology
Japanese
French

“Hi, my name is Victoria. I was born in France and moved to London to study Biomedical Sciences. Having been in an international school, I am bilingual in French and English and learnt other languages like Japanese. Alongside, I was ab...”

MyTutor guarantee

£20 /hr

Alexandra B.

Degree: Natural Sciences (Biologial) (Bachelors) - Cambridge University

Subjects offered: Biology, Maths+ 4 more

Biology
Maths
French
Chemistry
-Personal Statements-
-Oxbridge Preparation-

“About Me: I am a Natural Sciences student in my 2nd year at Cambridge, currently focusing more on the Biological side. Having seen the difference good teachers made in my own school career, I'm hoping to now pass this on!  Having had...”

MyTutor guarantee

£22 /hr

Francesco G.

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

Subjects offered: Biology, Science+ 9 more

Biology
Science
Philosophy and Ethics
Italian
Human Biology
Chemistry
.UKCAT.
.BMAT (BioMedical Admissions)
-Personal Statements-
-Medical School Preparation-

“Hello! My name is Francesco Grillo, I am a first-year Biomedical Science student in London, at King's College London. I am passionate about science, philosophy and languages.I was born in Rome (Italy). My first experience abroad was ...”

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

What is the Krebs/TCA/Citric Acid cycle?

What is the difference between a gene and an allele?

Outline the use of polymerase chain reaction (PCR) to copy and amplify minute quantities of DNA.

What are the key elements of an internal investigation?

View IB Biology tutors

Cookies:

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

mtw:mercury1:status:ok