Histology Practical

Question 1

Epithelial Tissue Characteristics:

Answer 1

It lines body cavities and hollow organs Covers the body surface – your skin is a barrier to the outside world Basal is the side of the epithelial cell that is in contact with the connective tissue below, and the apical (top) side is the free side, or the side that is exposed to the hollow space of the organ, cavity, or external surface of skin. Cells readily divide via mitosis to quickly replace damaged or dead cells. It is avascular (no blood vessels) –blood vessels in the underlying connective tissue deliver substances to the epithelial cells. Forms glands

Question 2

Simple Squamous:

Answer 2

Single layer of “squished” cells yields a very thin barrier Functions in easy passage, diffusion, of substances Found in capillaries and walls of the lung – both places requiring easy and quick exchange of substances

Question 3

Simple Cuboidal:

Answer 3

Single layer of cube like or wedge-shaped cells Functions in production and secretion of fluids such as sweat and oil. Also functions in reabsorption in the kidneys Found making up many of the glands in the body; also found in the walls of the kidney tubules

Question 4

Simple Columnar:

Answer 4

Single layer of columnar cells with nuclei aligned in a row; goblet cells are present to produce mucus Can be ciliated or nonciliated; ciliated found in the uterine tubes and nonciliated type lines the digestive tract Functions in providing a protective barrier, allows absorption of material

Question 5

Pseudostratified Ciliated Columnar:

Answer 5

Single layer of columnar cells with nuclei at different levels so it appears stratified Found in the respiratory tract from the nasal cavity, trachea, down the bronchi Ciliated to move mucus along

Question 6

Transitional:

Answer 6

Many cells – cuboidal shape near the basement membrane, and mushroom cap-like cells near the apical side. When stretched, the mushroom-cap cells flatten to squamous Functions in stretching as urine collects/passes through the organ Found in the walls of the ureters, urinary bladder, and the proximal urethra (portion right off of the bladder)

Question 7

Stratified Squamous:

Answer 7

Multiple layers of cells creating a thick membrane. Bottom cells are cuboidal or columnar and divide readily, surface cells are flattened. Can be keratinized or nonkeratinized. Functions in protecting the underlying tissue from abrasion Keratinized type makes up the epidermis of your skin, which is a dry surface. Nonkeratinized type is found in the moist linings of the esophagus, mouth, and the vagina.

Question 8

Answer 8

Simple Squamous Epithelium

Question 9

Answer 9

Simple Cuboidal

Question 10

Answer 10

Simple Columnar

Question 11

Answer 11

Pseudostratified Ciliated Columnar

Question 12

Answer 12

Transitional

Question 13

Answer 13

Stratified Squamous Kerantinized

Question 14

Answer 14

Stratified Squamous Nonkerantinized

Question 15

Muscle Tissue Characteristics

Answer 15

Cells have the appearance of a fiber

Muscle cells primary function is contraction, which is achieved by shortening of the muscle fiber by the sliding of protein filaments and overlapping over one another

Question 16

Skeletal Muscle

Answer 16

Long, cylindrical, striated (banded), parallel cells; many nuclei displaced to the periphery of the cell

Muscle cells (fibers) are attached to bones and are under voluntary (you have conscious control) control to move the skeleton

Found attached to the bones of the skeleton

Question 17

Answer 17

Skeletal Muscle

Question 18

Cardiac Muscle:

Answer 18

Cells are branched, striated, with one centrally located nucleus. Intercalated discs are present to join the cells to one another

Muscle cells (fibers) are under involuntary (you have no conscious control) control and allow for the contraction of the heart

Found only in the walls of the heart chambers, hence the name cardiac

Question 19

Answer 19

Cardiac Muscle

Question 20

Smooth Muscle:

Answer 20

Cells are spindle-shaped, no striations, with one centrally located nucleus. Smooth muscle is involuntary like cardiac muscle

Found in the hollow organs of the digestive tract, uterine wall, and blood vessels

Muscle cells (fibers) function in propelling food through the digestive tract, uterine contractions during labor, and regulating blood pressure by the contraction and dilation of blood vessels

Question 21

Answer 21

Smooth Muscle

Question 22

Connective Tissue Characteristics:

Answer 22

The most abundant tissue type in the body

All types of connective tissue have the same common embryonic origin (arise from same stem cell)– a mesenchyme cell

Unlike the epithelial tissue which includes cells bound to one another in one or many layers to create a barrier, the cells in connective tissue are sparse; therefore the “space” around the cells of connective tissue is actually made up of a material called the matrix.

Matrix consists of ground substance– fills the space between cells, fibers– collagen, elastin, and reticular, and cells– fibroblasts, chondroblasts, osteoblasts, and hematopoietic stem cells, etc.

Many functions: fills spaces, protects against infections, binds structures, produces blood cells, serves as framework, provides support and protection, stores fat, helps repair tissue damage

May be avascular (no blood vessels) i.e., cartilage, or have a high degree of vascularity i.e., bone.

Question 23

Loose Areolar Connective Tissue:

Answer 23

Composed of a gel-like matrix composed of all three types of fibers; collagen, elastin, & reticular. Cells present are fibroblasts, macrophages and other white blood cells.

Function is to wrap and support organs, the macrophages are part of the immune system so they function in getting rid of bacteria.

Location of this tissue is found throughout the body under the epithelial tissue, surrounds capillaries, and makes up the basement membrane which anchors the epithelial tissue above.

Question 24

Answer 24

Loose Areolar Connective Tissue

Question 25

Adipose Tissue (affectionately known as fat):

Answer 25

Matrix is sparse due to the large amount of fat stored in the cells. The tissue is packed with adipocytes (fat cells) with the nucleus pushed to the side by the large fat droplets.

Functions in protecting (cushioning) organs, extra fuel storage, insulation (preventing heat loss).

Location is around kidneys and eyeballs, in the abdomen and the breasts, and under the skin.

Question 26

Answer 26

Adipose Tissue

Question 27

Dense Regular Connective Tissue:

Answer 27

As the name implies, the tissue is packed, therefore “dense”, with collagen (mainly) and elastic fibers. There are two types: regular and irregular– this just refers to how those densely packed fibers are oriented– in a uniform, parallel, regular pattern, or packed in an irregular pattern (many different directions)

Functions in attaching muscles to bones (tendon), and bone to bone (ligaments). It can withstand great tensile strength if the tissue is stretched in one (this is the key word here) direction.

Location is in tendons, ligaments, and aponeuroses (layers of flat broad tendons found in abdominal, lumbar, plantar and palmar regions of the body).

Question 28

Answer 28

Dense Regular Pic

Question 29

Dense Irregular:

Answer 29

Matrix is made of densely packed collagen fibers arranged in an irregular pattern.

Functions in providing strength from tension exerted from many directions.

Located in the dermis of the skin (below epidermis), digestive tract, protective capsules that surround organs and joints

Question 30

Answer 30

Dense Irregular

Question 31

Hyaline Cartilage:

Answer 31

Firm, rubbery matrix with collagen fibers. Chondroblasts secrete the matrix and when mature (chondrocytes) are found in the lacuna.

The firm matrix supports and reinforces, resists compression and cushions.

Location of hyaline cartilage is nose, larynx, trachea, ends of long bones (for cushioning in the joint), costal cartilage of the ribs, and during development, forms most of the embryonic skeleton, before it later hardens into bone.

Question 32

Answer 32

Hyaline Cartilage

Question 33

Fibrocartilage:

Answer 33

Matrix similar to hyaline but less firm with many more collagenous fibers than hyaline cartilage.

Able to absorb compressive force and has great tensile strength.

Location is in intervertebral discs, pubic symphysis, and knee joints.

Question 34

Answer 34

Fibrocartilage

Question 35

Elastic Cartilage

Answer 35

Matrix is made up of elastic fibers which provides it with its flexibility.

The function of the tissue is to provide shape to the structure while providing flexibility. Notice location below.

Location is in the external ear (auricle), and the epiglottis.

Question 36

Answer 36

Elastic Cartilage

Question 37

Bone tissue:

Answer 37

Matrix is hard (hardest of all connective tissue types) and made up of mineral components called hydroxyapatite (calcium and other salts). Collagen is present to give flexibility to tissue. Osteocytes found in lacuna. Bone is highly vascularized.

Function of bone is for support and protection (by enclosing-think of your cavities), provides levers for muscle action, stores calcium and other minerals and fat; marrow inside of bones is site of blood cell formation.

Location: Bones.

Question 38

Answer 38

Bone Tissue

Question 39

Blood:

Answer 39

Fluid matrix (plasma) with red and white blood cells present.

Function is to transport nutrients, hormones, vitamins and minerals, respiratory gases, and other substances.

Blood is found only within the blood vessels.

Question 40

Answer 40

Blood

Question 41

Nervous Tissue:

Answer 41

Neurons are the large cells with branched processes that allow for impulse propagation. Glial cells (supportive cells) are also found in tissue.

Function of tissue is to transmit electrical impulses from the sensory receptors to the brain for interpretation and back to effector organs (glands and muscles).

Location of nervous tissue is in the brain, spinal cord, and nerves.

Question 42

Answer 42

Nervous Tissue