Microscopy and Tissue Types

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Questions and Answers

What is the primary function of epithelial tissue?

Storing fat and repairing damaged tissues

Transporting nutrients and wastes

Support and protection of organs and cells

Providing protection, secretion, absorption, and filtration (correct)

What is the main difference between a tissue and an organ?

A tissue is composed of two or more cell types, while an organ is composed of only one cell type

A tissue has a specific function, while an organ is a structural unit

A tissue is found only on the surface of the body, while an organ is found internally

A tissue is a group of cells, while an organ is a group of tissues (correct)

What is a characteristic of connective tissue?

It is found only in the skin

It is composed of only one cell type

It is used for support and protection of organs and cells (correct)

It provides protection, secretion, absorption, and filtration

How many divisions of muscular tissue are there?

3 Signup and view all the answers

What type of microscopy provides high-resolution images of intracellular structures and organelles?

Transmission electron microscopy (TEM) Signup and view all the answers

What is the function of the basement membrane in epithelial tissue?

To regulate what enters and leaves the cell Signup and view all the answers

In which organs can epithelial tissue be found?

Liver, kidney, skin, and lung Signup and view all the answers

What is the main function of serous membranes in the body?

To act as a lubricant to reduce friction from muscle movement Signup and view all the answers

What is the term for the potential space between the pleura, the two thin membranes that line and surround the lungs?

Pleural cavity Signup and view all the answers

Which of the following organs is fully encased by a serous membrane?

Liver Signup and view all the answers

What is the term for the fibrous sac that encloses the heart and great vessels?

Pericardium Signup and view all the answers

Which of the following is NOT a part of the serous membrane?

Fascia Signup and view all the answers

What is the term for organs that are not fully encased by a serous membrane?

Retroperitoneal Signup and view all the answers

What is the origin of serous membranes in embryonic development?

Mesoderm Signup and view all the answers

What is the primary function of pleural fluid in the pleural cavity?

To provide lubrication for the lungs during respiration Signup and view all the answers

What is the term for the areas where two surface membranes meet with a thin fluid-filled gap?

Potential spaces Signup and view all the answers

During gastrulation, what leads to the formation of internal organs with their distinct left-right arrangements?

The unequal activity of certain molecules and genes on both sides of the primitive streak Signup and view all the answers

What is the term for the segments of the external body that are connected to specific nerves?

Dermatomes Signup and view all the answers

What is the term for the structures that emerge during embryonic development and eventually form the heart?

Pericardial cavity Signup and view all the answers

What is the term for the molecules and genes that are not equally active on both sides of the primitive streak during gastrulation?

Gastrulation molecules Signup and view all the answers

What is the primary characteristic of adenocarcinoma?

It is a type of epithelial cancer that arises from glandular epithelium Signup and view all the answers

Which of the following is a function of the skin?

Touch, pressure, pain, and temperature regulation Signup and view all the answers

What is the origin of the epidermis?

Ectoderm Signup and view all the answers

What is the main function of the hypodermis?

To provide insulation and main blood supply to the skin Signup and view all the answers

Which of the following is a characteristic of the dermis?

It is a type of connective tissue derived from mesoderm Signup and view all the answers

What is the function of Langerhans cells in the epidermis?

To present antigens to the immune system and aid in immune response Signup and view all the answers

Which of the following organs has both exocrine and endocrine functions?

Pancreas Signup and view all the answers

What is the function of keratinocytes in the epidermis?

To form protective shields and provide strength to the skin Signup and view all the answers

Which type of cell is responsible for receiving the sensation of touch?

Merkel cells Signup and view all the answers

What is the primary function of sebaceous glands?

Waterproofing Signup and view all the answers

What is the characteristic of the epidermis?

Avascular and multilayered Signup and view all the answers

Which type of burn is also known as full thickness?

Third degree burn Signup and view all the answers

What is the function of the arrector pili muscle?

Erecting hair Signup and view all the answers

What is the composition of nails?

Hard layers of keratin Signup and view all the answers

What type of junction is found in the epidermis?

Tight junctions, desmosomes, gap junctions, and hemidesmosomes Signup and view all the answers

What is the location of basal cells in the epidermis?

Just above the basement membrane Signup and view all the answers

What is the main function of the epithelial layer that forms the outer layer of the skin?

To protect underlying layers Signup and view all the answers

Which type of epithelium allows tissue to expand and contract in response to fluid pressure?

Transitional epithelium Signup and view all the answers

What is the term for the epithelial layer that lines a body surface or cavity?

Epithelium Signup and view all the answers

What is the function of epithelial tissue that forms the lining of the urinary bladder?

To allow tissue to expand and contract in response to fluid pressure Signup and view all the answers

What is the term for the outer layer of the skin formed by keratinized epithelium?

Stratum corneum Signup and view all the answers

Which type of epithelium is characterized by cells that appear to be layered, but are not truly stratified?

Pseudostratified epithelium Signup and view all the answers

Study Notes

Microscopy

Scanning electron microscopy (SEM) reveals cell surface details
Transmission electron microscopy (TEM) provides high-resolution images of intracellular structures and organelles

Tissue Organization

Cell → Tissue → Organ → System
Tissue: a collection of cells that are adapted to perform a specific function
Organ: two or more tissues combined to create a structural unit that has a particular function

Types of Tissue

Epithelial Tissue

Covers body surface, forms lining for internal cavities
Provides protection, secretion, absorption, and filtration
Contains basement membrane
Found in liver, kidney, skin, lung

Connective Tissue

Used for support and protection of organs and cells
Transports nutrients and wastes, defends against pathogens, stores fat, and repairs damaged tissues
Examples: cartilage, bone, blood, tendon, ligament

Muscular Tissue

Has three divisions

Serous Membranes

Formed from mesoderm
Lines body wall and covers internal organs
Acts as a lubricant to reduce friction from muscle movement
Has three parts: visceral membrane, parietal membrane, and cavity

Specific Serous Membranes

Peritoneum

A serous membrane that encases organs
Intraperitoneal organs are fully encased by serous membrane

Pericardium

A fibrous sac that encloses the heart and great vessels

Retroperitoneal

Organs are not fully encased by serous membrane

Pleural Cavity

The space between the pleura, the two thin membranes that line and surround the lungs
Contains a small amount of liquid known as pleural fluid, which provides lubrication during respiration

Pericardial Cavity

Plays a critical role in protecting and supporting the heart

Body Organization

The human body is symmetrical externally but asymmetrical internally
External body is organized into segments called dermatomes, which come from somites
Each dermatome is connected to a specific nerve
Left-right differences occur due to uneven activity of molecules and genes during gastrulation

Potential Spaces

Small spaces that have the potential to expand
Not rigid
Technical definition: areas where two surface membranes meet with a thin fluid-filled gap
Examples: serous membranes, fascia planes, and collapsible tubes/spaces

Epithelia

Epithelia is a sheet of cells that covers a body surface or lines a body cavity
Nearly all substances received or given off by the body must pass through an epithelium layer
Types of epithelia include keratinized, pseudostratified, and transitional epithelium

Keratinized Epithelium

Forms the outer layer of the skin
Protects underlying layers

Pseudostratified Epithelium

No additional information provided

Transitional Epithelium

Allows tissue to expand and contract in response to fluid pressure
Found in the inner walls of the urinary bladder, allowing it to expand when filling with urine

Skin

The skin is the largest organ of the body
Acts as a physical barrier, protecting against infection, physical damage, and chemical damage
Regulates touch, pressure, pain, and temperature

Layers of the Skin

Epidermis:
- Derived from ectoderm
- Keratinized stratified squamous epithelium
- Contains keratinocytes (protective shields) and Langerhans cells
- 4 layers: horny layer (stratum corneum), granular layer, spinous layer, and basal layer
Dermis:
- Dense connective tissue derived from mesoderm
- Contains fibroblasts, collagen, blood, mast cells, receptors, and nerves
- Provides flexibility and strength to the skin
Hypodermis (subcutaneous tissue):
- Main blood supply for the rest of the skin
- Provides insulation

Skin Appendages

Hair:
- Used for thermal regulation and display
- Associated with arrector pili muscle and sebaceous glands
Nails:
- Provide physical protection
- Composed of hard layers of keratin
Sweat glands:
- Eccrine and apocrine glands
- Help regulate body temperature

Burns

First and second degree burns:
- Partial thickness burns, not affecting all skin layers
- Example: sunburn
Third degree burns:
- Full thickness burns, affecting all skin layers and some underlying tissues

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Description

Compare TEM and SEM, and identify simple and compound tissue types. Learn about embryology, normal range, and congenital problems.