Lecture Exam II

Robert Hooke

(1665)

Antoni van Leeuwenhoek

(1632-1723)

Theodor Schwann and Matthias Jakob Schlieden

Schwann (1839) and Schlieden (1838)

"all living organisms are composed of one or more nucleated cells and that the nucleated cell is the basic functional unit of living organisms.

Rudolf Virchow

(1858) coined the term biogenesis; all life comes from preexisting cells. But didn't have proof

Louis Pasteur

(1862) supplied the proof for biogenesis.

Cell Theory

1. The cell is the functional unit of living organisms (Schwann & Schlieden)

2. All living organisms are composed of nucleated cells (Schwann & Schlieden)

3. Cells arise only by division of pre-existing cells (Biogenesis; Virchow & Pasteur)

Cytology

the study of cells

Cellular Size

cell size is limited by the surface-area-to volume ratio. Volume increases more rapidly that surface area. Smaller cell= more surface area/volume ratio

Cell Structure

Plasma membrane, cytoplasm, organelles (little organs), inclusions (vacule and adipost)

Protoplasm

living matter (nucleus and cytoplasm)

Cell/Plasma membrane

the outer limiting membrane that separate the cells internal part from the extracellular fluid and external enviroment

As a result of the aging process, hair follicles produce ____________ hairs.

thinner

The major functions of merocrine sweat glands are _________

secretion, protection and thermoregulation

True or False: Bone growth begins during embroyic development

True

Ligaments

connect bone to bone

Tendons

connect tissue to bone

Integumentary system consists of...

the skin and its derivatives: nails, hair, sweat glands and sebaceous (oil) glands

Four types of Epidermis

Keratinized, stratified, squamous, epithelium

Subcutaneous layer (hypodermis)

deep to the dermis, a layer of areolar and adipose connective tissue

Layers of Epidermis (from deep to superficial)

stratum basale, stratum spinosum, stratum granulosum, stratum licidum (found in thick skin only) and stratum corneum.

Stratum Basale (basal layer)

the deepest epidermal layer. Single layer of cuboidal to low columnar cells tightly attached to an underlying basement membrane that separated the epidermis from the connective tissue of the adjacent dermis.

Tactile cells (Merkel cells)

sensitive to touch and when compressed they release chemicals that stimulate sensory nerve endings, providing information about objects touching the skin.

Epidermal dendritic (Langerhans) cells

a fourth cell type in the stratum spinosum. Immune cells that help fight infection in the epidermis

Anucleate

dead, scaly interlocking keratinized cells that are tightly packed 20-30 layers thick in the stratum corneum

How thick is skin? (both thin and thick)

Thin skin is 0.075 mm to 0.150 mm thick

Thick skin is 0.4 to 06 mm thick

How long do keratinocytes stay in the stratum corneum?

about 1 month

What is the amount of melanin the skin determined by?

Heredity and light exposure

Hemangioma

is an anomaly that results in skin discoloration due to blood vessels that proliferate to form a benign tumor

Capillary hemangiomas

"strawberry birthmarks", appear on the skin as bright red to deep purple nodules that are usually present at birth and disappear in childhood.

Striae

when skin is streched beyond its capacity and collagen fibers are torn and result in stretch marks

Functions of the Subcutaneous Layer

1. stabilize the position of the skin

2. pads and protects the body

3. energy reservoir

4. thermal insulation

Why are drugs often injected into the subcutaneous layer?

because its extensive vascular network promotes rapid absorption

Vitamin D (cholecalciferol)

synthesized from a steroid precursor by the keratinocytes when they are exposed to ultraviolet radiation.

What is the release of water vapor from sweat glands when we are not sweating?

Transpiration

Transdermal administration

drugs that are soluble either in oils or lipid soluble carriers may be administered transdermally by an adhesive path that keeps the drug in contact with the skin surface.

What do touch receptors detect?

heat and cold, pressure, and vibration

Tactile cells are described by... (4)

1. can be stimulated by light touch

2. can be stimulated by light pressure

3. large epithelial cells

4. Merkel cells

Why is the lunula whitish?

the whitish appearance because a thickened stratum basal obscures the underlying blood vessels.

Functions of Hair

protection, facial expression, heat retention, sensory reception, visual identification, and chemical signal dispersal

What causes grey hair?

the gradual reduction of melanin production within the hair follicle, white hair is the complete stoppage of melanin production

Two types of Exocrine glands

1. Sweat (sudoriferous) glands

2.. Sebaceous glands

Two types of Sweat glands

1. Merocrine (ecrine) sweat gland

2. Apocrine sweat gland

. True or False: Merocrine sweat glands diminish with age

True

Merocrine Sweat Glands

are the most numerous and widely distributed sweat glands. Simple, coiled tubular glands that discharge their secretions directly onto the surface of the skin (sweat).

Aprocine Sweat Glands

coiled, tubular glands that release their secretion into hair follicles

Comedo

A sebaceous gland plugged with sebum. Open comedo are blackheads, closed comedo are whiteheads

Papule or Pustule

dome-shaped lesions, filled with fluid and form red relations on the skin but do not contain pus.

Become pustules, which are filled with white blood cells, dead skin cells and bacteria (pus)

Nodule

similar to pustuale but extending deeper into the skin layers usually rupturing the hair follicle wall. Prone to scarring

Cyst

large, fluid-filled nodule that can become severly inflamed and painful and can lead to scaring of the skin.

Sebaceous Glands secreation

oily, waxy secretion that is stimulated by hormones during puberty of both sexes.

Ceruminous glands

modified apocrine sweat glands located only in the external acoustic meatus (ear canal) where their secretion forms a waterproof earwax called cerumen

Cerumen

waterproof earwax

When are the mammary glands functional?

In pregnant and lactating females

Regeneration

the replacement of damaged or dead cells with the same cell type

Fibrosis

the process of scar tissue deposition during healing, binds damaged parts together

Stages of Wound Healing (4)

1. Cut blood vessels initiate bleeding into the wound. The blood brings clotting proteins, numerous white blood cells and antibodies.

2. A blood clot forms, patching the edges of the wound together and preventing pathogens from entering

3. The cut blood vessel regenerates and grows in the wound. A soft, mass deep in the would becomes granulation tissue.

4. Epithelial regeneration of the epidermis occurs due to division of epithelial cells on the edges of the wound

Granulation Tissue

vascular connective tissue that initially forms in a healing wound

What are not repaired in the Integumentary system? (4)

hair follicles, exocrine glands, nerves and the arrestor pili muscle cells

First- degree burns

superficial burns, involve only the epidermis and are characterized by redness, pain and slight edema.

Second-degree burns

involve the epidermis and part of the dermis.

Periderm

a covering layer of the ectoderm that forms a layer of squamous epithelium that flattens

Vernix caseosa

the waterproof protective coating on the skin of a fetus produced by the the sloughed-off cells mixed with sebum secreted by the sebaceous glands

During the embryonic period the mesoderm becomes ________

mesenchyme

Basal cell Carcinoma

most common and least dangerous from of skin cancer

Squamous cell Carcinoma

arises from keratinocytes of stratum spinosum

Malignant Melanoma

most deadly and aggressive form of skin cancer. Arises from melanocytes in preexisting moles

Compact bone

dense connective bone tissue that appears white, smooth and solid. 80% of the total bone mass

Spongy bone

located internal to compact bone. It appears porous and makes up 20% of the total bone mass

Cartilage

semirigid connective tissue that is more flexible than bone

Two types of Cartilage

1. Hyaline cartilage

2. Fibrocartilage

Hyaline cartilage

attaches the ribs to the sternum, covers the ends of bones and is the cartilage between growth plates

Fibrocartilage

weight-bearing cartilage that withstands compression it forms the intervertebral discs, pubic symphysis and cartilage pads of the knee joints

True or False: Bones provide structural support and serves as a framework for the entire body

True

Bones function as a system of _______

levers

Hemopoiesis

the process of blood cell plasma production

What two minerals are in bone? What is their purpose?

1. Calcium; muscle contraction

2. Phosphate; structural component of ATP, nucleotides and phosolipids

Long bones (with example)

greater in length than width

Examples: upper limbs (arm, forearm), lower limbs (thigh, leg)

Short bones (with example)

length nearly equal to their width

Example: carpals (wrist), tarsals (foot)

Flat bones (with example)

flat, thin surface that may be slightly curved. Provide extensive surface for muscle attachment and protect underlying soft tissue

Example: sternum, skull, scapulae

Irregular bones (with example)

elaborate, sometimes complex shapes that do not fit into any other categorie

Example: vertebrae, hip bones and some in the skull

Diaphysis

elongated usually cylindrical shaft of the long bone provides leverage and major weight support

Medullary cavity

hollow, cylindrical space within the diaphysis

Articular cartilage

thin layer of cartilage that covers the joint surface of the epiphysis

Metaphysis

the region in a mature bone sandwiched between the diaphysis and the epiphysis

Endosteum

an incomplete layer of cells that covers all internal surface of the bone within the medullary cavity. Contains osteoprofenitor cells, osteoblasts, and osteoclasts

nutrient foramen

small opening or hole in the bone that has one nutrient vein and one nutrient artery

Osteoprogenitor cells

stem cells derived from mesenchyme

Osteoblasts

formed from osteoprogenitor stem cells. Somewhat cuboidal shape and have abundant rough endoplasmic reticulum and Golgi apparatus

Osteoid

semisolid organic form of bone matrix

Osteocytes

mature bone cells derived from osteoblasts that have lost their bone-forming ability when enveloped by calcified osteoid

Osteoclasts

large multi-nucleated phagocytic cell that reabsorbs bone matrix.

Osteon

small cylindrical structures that are the basic functional and structural unit of mature compact bone. Orientated parallel to the diaphysis of the long bone

Central canal

cylindrical channel that lies in the center of the osteon and runs parallel to it, extending through the central canal are blood vessels and nerves that supply the bone

Canaliculi

tiny, interconnecting channels within the bone connective tissue that extend from each lacuna, travel through the lamellae and connect to other lacunae and the ventral canal. House osteocyte cytoplasmic projects that permit intercellular contact and communication.

Chondroblasts

derived form mesenchymal cells and produce cartilage matrix

Chondrocytes

when chondroblasts become encased within the matrix they become chondrocytes

Lacunae

the small spaces occupied by chondrocytes

Stages of Interstitial Growth (3)

1. chondrcyte in lacuna undergoes mitosis

2. two cells occupy one lucuna

3. two cells in one lucuna begin to produce a new matrix

True or False: Spongy bone contains osteons

False

Trabeculae

open lattice of narrow rods and plates of bone contained in spongy bone