Besides acting as mechanical barriers, the skin epidermis and mucosae of the body have other att

Besides acting as mechanical barriers, the skin epidermis...

Key Concepts

Cilia

Cilia are hair-like projections found on the surface of epithelial cells, particularly in the respiratory tract. They beat in a coordinated manner to move mucus, along with trapped pathogens and debris, toward the throat where it can be expelled or swallowed, thus assisting in the clearance of harmful agents.

Acid pH

An acidic pH in certain skin regions and bodily secretions creates an inhospitable environment for many pathogens. The low pH level disrupts microbial growth and survival, thereby playing a crucial role in maintaining the integrity and protective function of epithelial barriers.

Keratin

Keratin is a fibrous structural protein that is abundant in the epidermis of the skin. Its robust and resilient nature provides mechanical strength and durability, forming a protective shield that is resistant to physical and chemical damage, and helps prevent water loss.

Mucus

Mucus is a viscous secretion produced by goblet cells and mucous glands that lines mucosal surfaces. It acts as a physical trap for dust, microbes, and other particulates, while also containing antimicrobial molecules that neutralize pathogens, thereby preventing their entry and establishment in the body.

Mucosae

Mucosae are moist linings found in various body cavities such as the respiratory, gastrointestinal, and urogenital tracts. They secrete mucus and are equipped with mechanisms to trap and eliminate pathogens, thereby serving as a vital first line of defense in internal environments where constant exposure to foreign particles occurs.

Skin Epidermis

The skin epidermis is a multilayered structure that not only forms a physical barrier against environmental insults and pathogens but also actively participates in immune responses. This outermost layer of the skin contains specialized cells and proteins that help maintain hydration and shield the body from external chemicals and radiation.

Lysozyme

Lysozyme is an antimicrobial enzyme found in various secretions including mucus, saliva, and tears. It functions by breaking down the peptidoglycan component of bacterial cell walls, thereby inhibiting bacterial replication and contributing to the innate immune defense.

Transcript

00:01 Alrighty, so for this problem, we have some of these mechanical barriers of the body, and we're just going to cite some places we find it in these problems.

00:13 So we're really just looking at these adaptive body defenses.

00:17 And so the first one is going to be mucus.

00:30 Okay, well, one place we find this is on the outer surface of our eyes.

00:36 Our eyeballs are kind of slimy feeling.

00:40 If you've ever touched your eyeball, you would know that.

00:49 And it's also found in many of our body cavity linings.

01:02 So if we think about the intestines, you know, having a layer of mucus there really helps with moving matter through the lining without causing rips and tears and damage.

01:31 Okay, and so the next is the lysosime.

01:46 All right, so this is an enzyme, and its job is to destroy bacteria.

02:00 So it's good for keeping us healthy, for sure.

02:03 And where it's found is in saliva.

02:10 And so every time we touch a bacterial covered doorknob and then touch a sandwich and put it into our mouth, we have this lysosheim in our saliva to help kill some of the bacteria that we may be about to ingest.

02:31 All right, so moving down the list, we are on to keratin.

02:40 Okay, so this is a protein.

02:45 It's kind of a waterproofing protein, if you want to think of it as such.

02:55 And it's found in epithelial or skin membranes.

03:09 So what this does is presents a barrenes.

03:17 To microorganisms on the skin.

03:28 So we'll say microorgs on skin.

03:32 Essentially, the keratin in our skin, so if this is an arm, really small microorganisms that might want to dig in there and cause havoc are going to be kept on the outside by the keratin that's in our skin.

03:54 So it's just this tough wall that's hard...

Please give Ace some feedback