The cells in the SEM are epithelial cells from the small intestine. Discuss how aspects of their

step 1 Today we will be discussing the small intestine. So just in overview, the small intestine is gen

The cells in the SEM are epithelial cells from the small...

Key Concepts

Tight Junctions

Tight junctions are complexes of proteins that seal adjacent epithelial cells together at their apical ends. Their role is to regulate paracellular transport, ensuring that substances pass through cells rather than between them. This barrier is critical in the intestine to prevent the leakage of potentially harmful substances and to maintain the selective absorption environment necessary for proper nutrient uptake.

Epithelial Cell Polarity

Epithelial cell polarity refers to the asymmetrical organization of cellular components, which results in distinct apical and basolateral surfaces. This polarity is key for directional transport; the apical surface interfaces with the intestinal lumen for nutrient absorption, while the basolateral surface interacts with blood vessels for nutrient distribution. This separation of functions is fundamental to maintaining a selective barrier between the intestine and the bloodstream.

Microvilli

Microvilli are small, finger-like projections found on the apical surface of epithelial cells that drastically increase the cell's surface area. In the small intestine, this expansion of the membrane is crucial for enhancing the absorption of nutrients by providing more area for enzymes and transport proteins to interact with digested food, thereby facilitating more efficient nutrient uptake.

Transcript

00:01 Today we will be discussing the small intestine.

00:04 So just in overview, the small intestine is generally used for absorbing nutrients after we conceive soma meal.

00:13 So once we consume a mill, it is then digested in the stomach and turned into kym.

00:19 That time is that transported to the small intestine were further digestion, and then absorption occurs.

00:28 So there's three segments of the small intestine.

00:31 There's the duodenum, the jejune, um, and the ilium.

00:34 Digestion mainly occurs in the duodenum and then in the d june.

00:38 Um, and the ilium is where the majority of our nutrient absorption occurs.

00:47 So i've drawn to structures.

00:49 This first one in its entirety is the villas, so the villas plays a major role within absorption.

00:59 In terms of increasing the surface area of the intestinal lining, increasing the surface area increases the absorption of the nutrients that our body needs, um and therefore improving the amount of nutrients we take in.

01:19 So on the outsides of this feel us as you can see their small finger like projections called micro villi thes attached to molecules within the body.

01:30 After again after we go through digestion, their molecules that are outside and the micro ville i attached to them further improving the entire process of absorption.

01:44 So within the villas, it is lined with these epithelial cells.

01:50 This is a singular or single layer of epithelial column er epithelial cells called entero sites within the villus.

02:03 We have capillaries, thes capital aries, our great about absorbing nutrients, um, especially water soluble nutrients and small molecules.

02:18 So water soluble molecules and other small molecules, for instance, as we will come back thio.

02:26 There's sodium glucose amino acids, assets which eventually may help in protein formation.

02:36 And we have htoo.

02:38 So these are all the molecules that are absorbed through the capillaries and then transported to other parts of the body.

02:45 Um, there's also things such a small fatty assets that travel through the capillaries and are absorbed on been transported to the rest of the body.

02:56 So the last part of the villas that will look at is this elongated structure that's kind of parallel as well as perpendicular...

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