biology

Pectinate muscles

Pectinate muscles is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pectinate muscles rather than just read about it. In short: The pectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of the atria of the heart. Structure In the atria of the heart, there are two different types of walls.

Key takeaways

Pectinate muscles belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pectinate muscles to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pectinate muscles from memory before moving on to harder problems.

Reference excerpt

The pectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of the atria of the heart.

Structure In the atria of the heart, there are two different types of walls. Behind the crest (crista terminalis) of the right atrium, also known as the posterior wall, the internal surface is smooth. This is called the sinus venarum. The pectinate muscles make up the part of the anterior wall, the wall in front of the sinus venarum, the right atrial appendage. In the left atrium, the pectinate muscles are confined to the inner surface of its atrial appendage. They tend to be fewer and smaller than in the right atrium. This is due to the embryological origin of the auricles, which are the true atria. Some sources cite that the pectinate muscles are useful in increasing the power of contraction without increasing heart mass substantially. Pectinate muscles of the atria are different from the trabeculae carneae, which are found on the inner walls of both ventricles. The pectinate muscles originate from the crista terminalis.

Name The pectinate muscles are so-called because of their resemblance to the teeth of a comb, as in pecten.

References This article incorporates text in the public domain from page 529 of the 20th edition of Gray's Anatomy (1918)

External links MedEd at Loyola grossanatomy/dissector/labs/thorax/heart/he3_1b.htm Anatomy photo:20:13-0104 at the SUNY Downstate Medical Center Atlas image: ht_rt_atrium at the University of Michigan Health System - "Right atrium, internal structure, anterior view"

Illustrations

Worked examples

Example 1 — a first encounter with Pectinate muscles

Start with the simplest possible case. Write down what Pectinate muscles claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pectinate muscles before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pectinate muscles ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pectinate muscles

In research: Pectinate muscles appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pectinate muscles in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pectinate muscles is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cardiac anatomy, Cardiovascular system stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Pectinate muscles outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pectinate muscles in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pectinate muscles means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pectinate muscles out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pectinate muscles in simple terms?

The pectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of the atria of the heart. Structure In the atria of the heart, there are two different types of walls.

Why does Pectinate muscles matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pectinate muscles?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pectinate muscles.