biology

Parenchyma

Parenchyma 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 Parenchyma rather than just read about it. In short: Parenchyma () is the bulk of functional substance in an animal organ such as the brain or lungs, or a structure such as a tumour. In zoology, it is the tissue that fills the interior of flatworms.

Key takeaways

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

Reference excerpt

Parenchyma () is the bulk of functional substance in an animal organ such as the brain or lungs, or a structure such as a tumour. In zoology, it is the tissue that fills the interior of flatworms. In botany, it is some layers in the cross-section of the leaf.

Etymology The term parenchyma is Neo-Latin from the Ancient Greek word παρέγχυμα parenchyma meaning 'visceral flesh', and from παρεγχεῖν parenkhein meaning 'to pour in' from παρα- para- 'beside' + ἐν en- 'in' + χεῖν khein 'to pour'. Originally, Erasistratus and other anatomists used it for certain human tissues. Later, it was also applied to plant tissues by Nehemiah Grew.

Structure The parenchyma is the functional parts of an organ, or of a structure such as a tumour in the body. This is in contrast to the stroma, which refers to the structural tissue of organs or of structures, namely, the connective tissues.

Brain The brain parenchyma refers to the functional tissue in the brain that is made up of the two types of brain cell, neurons and glial cells. It is also known to contain collagen proteins. Damage or trauma to the brain parenchyma often results in a loss of cognitive ability or even death. Bleeding into the parenchyma is known as intraparenchymal hemorrhage.

Lungs Lung parenchyma is the substance of the lung that is involved with gas exchange and includes the pulmonary alveoli.

Liver The liver parenchyma is the functional tissue of the organ made up of around 80% of the liver volume as hepatocytes. The other main type of liver cells are non-parenchymal. Non-parenchymal cells constitute 40% of the total number of liver cells but only 6.5% of its volume.

Kidneys The renal parenchyma is divided into two major structures: the outer renal cortex and the inner renal medulla. Grossly, these structures take the shape of 7 to 18 cone-shaped renal lobes, each containing renal cortex surrounding a portion of medulla called a renal pyramid.

Tumors The tumor parenchyma, of a solid tumour, is one of the two distinct compartments in a solid tumour. The parenchyma is made up of neoplastic cells. The other compartment is the stroma induced by the neoplastic cells, needed for nutritional support and waste removal. In many types of tumour, clusters of parenchymal cells are separated by a basal lamina that can sometimes be incomplete.

Flatworms Parenchyma is the tissue made up of cells and intercellular spaces that fills the interior of the body of a flatworm, which is an acoelomate. This is a spongy tissue also known as a mesenchymal tissue, in which several types of cells are lodged in their extracellular matrices. The parenchymal cells include myocytes, and many types of specialised cells. The cells are often attached to each other and also to their nearby epithelial cells mainly by gap junctions and hemidesmosomes. There is much variation in the types of cell in the parenchyma according to the species and anatomical regions. Its possible functions may include skeletal support, nutrient storage, movement, and many others.

References

External links The dictionary definition of parenchyma at Wiktionary

Illustrations

Worked examples

Example 1 — a first encounter with Parenchyma

Start with the simplest possible case. Write down what Parenchyma 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 Parenchyma 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 Parenchyma 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 Parenchyma

In research: Parenchyma 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 Parenchyma 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: Parenchyma is common in secondary-school and first-year university syllabi. It links to neighbouring topics Tissues (biology), so understanding it makes those chapters shorter.
In everyday life: Look for Parenchyma 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 Parenchyma in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Parenchyma 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 Parenchyma out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Parenchyma in simple terms?

Parenchyma () is the bulk of functional substance in an animal organ such as the brain or lungs, or a structure such as a tumour. In zoology, it is the tissue that fills the interior of flatworms.

Why does Parenchyma 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 Parenchyma?

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 Parenchyma.