Midterm Flashcards
4 types of tissues
Epithelial, Connective, Muscular, Nervous
Types of intercellular junctions
Tight, adherens, desmosomes, hemidesmosomes, gap
Tight intercellular junction
Inhibit passage of substance between cells and prevents leakage from the organs such as stomach and urinary bladder
Adherens junction
Helps resist separation during contractile activities like peristalsis in the GI tract
Desmosomes junction
Prevents epithelial cells from getting separated under tension and cardiac muscle cells from pulling apart during contraction
Hemidesmosomes junction
Helps anchor cells to the basement membrane
Gap junction
Seen in nerve and muscle cells where the cells transmit electrical signals
Epithelial tissue
Cells (many) are densely packed with little to no ECM
Tissue is avascular
They form covering and lining layer and not covered by other tissues
Provides protection, carries out filtration, secretion, absorption, and excretion
Connective tissue
Fewer cells separated by lots of ECM
Most connective tissues are highly vascular
They bind cells within tissues and compartmentalizes organs like skeletal muscles
It protects, supports, and strengthens other body tissues and insulate internal organs
On what basis are the covering and lining epithelia classified?
- Arrangement of cell layers, and
- Shape of their cells
Cell layers
Simple, Pseudostratified, and Stratified
Shape of cells
Squamous, Cuboidal, and Columnar
Simple squamous
one row of flat cells – Endothelium, Mesothelium, Alveoli (air sacs)
stratified squamous
multilayered – non-keratinized (mouth); keratinized (epidermis of skin)
Simple cuboidal
one layer of cube-like cells - kidneys), stratified cuboidal (sweat glands)
Simple columnar
one row of tall, column-like cells - GI tract organs like stomach and intestines
pseudostratified columnar
may be ciliated like in the respiratory tract organs like trachea, stratified columnar (rare – male urethra)
Endocrine glands
ductless and secrete hormones into the interstitial fluid and then transported in the blood. E.g., Pituitary gland, Thyroid gland, Adrenal gland
Exocrine glands
have ducts to carry their secretions on to the body surface. E.g., Salivary gland, Sweat gland, Mammary glands
Simple tubular
Large intestinal glands
Simple branched tubular
Gastric glands of the stomach
Simple coiled tubular
Sweat glands
Simple acinar
Penile urethral glands
Simple branched acinar
Sebaceous glands
Compound tubular
Bulbourethral glands (male)
Compound acinar
Mammary glands
Compound tubuloacinar
Pancreatic acinar glands
Merocrine glands
cells secrete substances in secretory vesicles via exocytosis – salivary gland
Apocrine glands
accumulate product in apical portions of cells with the portion of cells getting pinched off that form part of secretion – mammary glands
Holocrine glands
secretions stored in cytosol; mature cell ruptures and dies and become the secretory product – sebaceous (oil) gland
Most abundant tissue in the human body
Connective tissue
What is an extracellular matrix (ECM) and why is ECM important for the connective tissue?
The materials found between the cells within a tissue and made of protein fibres and ground substances. The ECM keeps the cells bound together and support cells while giving adequate space for blood vessels, lymphatic vessels, and nerves to pass through. It helps determine a specific connective tissue’s qualities whether they are fluid, flexible or firm and rigid.
Into which category can we place hyaluronic acid, when studying connective tissue and what is its importance
Hyaluronic acid is a polysaccharide that is viscous, slippery substance and found in the ground substance of connective tissues. It keeps cells bound together, keeps water contained in the tissues such as joint cavity, and maintain the shape of the eyeballs
What is the nervous tissue made up of and what role do these cells play with the tissue?
Made of neurons (nerve cells – primary cells that transmit nerve impulses) and neuroglia (glial cells – support and protect neurons)
What are the effects of aging on tissues?
stiffening + loss of elasticity in tissues
The integumentary system is composed of
the skin, hair, oil and sweat glands, nails, and sensory receptors
Who is a dermatologist?
is the medical specialty that deals with the structure, function, and disorders of the integumentary system
Another name for skin is
cutaneous membrane
The superficial skin
Epidermis
Epithelial tissue
The deeper skin
Dermis
Connective tissue
functions of the Integumentary system
body temperature regulation
blood storage
protection
sensation
excretion and absorption
synthesis of vitamin D
The integumentary system contributes to homeostasis by
protecting the body and helping regulate body temperature. It also allows you to sense pleasurable, painful, and other stimuli in your external environment
Avascular
The epidermis, won’t bleed when cut
Vascular
Dermis, will bleed when cut
What is the layer called deep to the dermis
Subcutaneous/hypodermis. Consists of areolar and adipose tissues
Subcutaneous layer
serves as a storage depot for fat and contains large blood vessels that supply the skin
4 main types of cells in the epidermis of the skin
Keratinocytes (90% of cell populations)
Melanocytes (8% of cell population)
Langerhans cell (a small fraction)
Tactile/merkel cells (least numerous)
Melanin
responsible for the production of yellow-red or brown-black pigment and that contributes to skin colour and absorbs damaging UV light.
5 strata layers
stratum basale
stratum spinosum
startum granulosum
stratum lucid
stratum corneum
Stratum basale
deepest (bottom-most) layer of the epidermis and is composed of a single row of cuboidal or columnar keratinocytes cells. This layer contains epidermis stem cells that undergo cell division to continuously produce new keratinocytes
stratum lucidum
consists of four to six layers of flattened clear, dead keratinocytes that contain large amounts of keratin and thickened plasma membranes
stratum spinosum
Intraepithelial macrophages (cells) also known as Dendritic cells and projections of melanocytes cells can be found in this stratum
stratum Granulosum
keratohyalin, which assembles keratin intermediate filaments into keratin. The cells also contain membrane enclosed lamellar granules, which release a lipid-rich secretion which acts as a water repellent sealant
stratum corneum
consists of 25 to 30 layers of flattened dead keratinocytes. However, the number of layers can vary in thin and thick skin
callus
An area of hardened and thickened skin that is usually seen in palms and soles and is due to persistent pressure and friction
Keratinization
happens when newly formed cells in the stratum basale are slowly pushed to the surface
How many days does it take for the cells in the stratum basale to reach the top and get sloughed off?
seven to ten weeks
Albinism
inherited inability of a person unable to produce melanin due to the melanocytes unable to synthesize Melanin
The part of hair that can be seen on the surface of a hairy skin is called the
Hair shaft
In hairy skin the part that lies deep in the dermis is called the
Hair root
Hairs are growths of
epidermis composed of dead, keratinized epidermal cells
hirsutism
The condition whereby females exhibit excessive body hair in areas that are usually not hairy
Lanugo
covers body of fetus
Vellus
short, fine, pale hairs
Terminal
Long, coarse, heavily pigmented hairs
functions of sebaceous glands
Sebum also prevents excessive evaporation of water from the skin
keeps the skin soft and pliable
inhibits the growth of some (but not all) bacteria
eccrine sweat glands
responsible for maintaining homeostatic regulation of body temperature
Apocrine sweat cells
Sweat produced from hormones
4 Deep Wound Healing Phases
Inflammatory phase
Migratory phase
Proliferative phase
Maturation phase
Inflammatory phase
inflammation; blood clot forms in the wound and loosely unites wound edges
Migratory phase
clot becomes a scab; epithelial cells migrate beneath scab to bridge wound 。damaged blood vessels begin to regrow
Proliferative phase
growth of epithelial cells beneath scab + continued growth of blood vessels
Maturation phase
scab falls off once epidermis is restored to normal thickness
Which pigment secreted by specialized cells in the skin is capable of absorbing ultraviolet light
Melanin
Constant exposure of skin to friction stimulates the formation of a callus which is the thickening of the _____ of the epidermis
Stratum corneum
Which of the structures found in skin plays an important role in thermoregulation
Sweat glands
What are accessory structures of the skin
Hair
Nails
Sweat glands
Sebaceous glands
These cells are predominantly found in the epidermis of the skin
Keratinocytes
the 6 functions of the bone tissue
support
protection,
movement
mineral homeostasis
blood cell production
triglyceride storage
medical term for blood cell production is
hematopoiesis
6 types of bone where red bone marrow can be found
axial flat bones (cranial bones, clavicle, sternum, ribs, scapula, vertebrae, and pelvis) and the proximal ends of the humerus and femur.
Diaphysis
(shaft), proximal and distal epiphyses (connect at joints)
metaphyses
between D and E, contains epiphyseal plate
articular cartilage
hyaline cartlige that reduces friction and absorbs shock at joints
periosteum
Connective tissue surrounding the diaphysis
medullary cavity
contains yellow bone marrow and minimizes bone weight
Endosteum
Thin membrane lining the medullary cavity
Four types of cells are present in bone tissue
osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts
Osteoprogenitor cells
Bone stem cells able to differentiate into the other types of cells
Develops into an osteoblast
Osteoblasts
Bone building cells that secrete matrix
Forms bone Extracellular matrix
Osteocytes
Mature bone cells
Maintains bone tissue
Osteoclasts
Remodel bones and cause them to release calcium
Functions in resorption, the breakdown of bone Extracellular matrix
Compact bone
Good at providing protection and support
tissues denser, resists the stresses produced by weight and movement arranged in repeating structural units called osteons and they construct the external layer of the bones
Spongy bone
Lightweight and provides tissue support
Lacks osteons, lamellae are arranged in a lattice of thin columns called trabeculae, trabeculae support and protect the red bone marrow, hemopoiesis occurs in this.
Which of the four bone cells, is responsible for regulating blood calcium levels?
osteoclasts
Loose connective tissue in bone
holds organs in place and attaches epithelial tissue to other underlying tissues
Dense connective tissue in bone
helps attach muscles to bones and link bones together at joints
The repeating structural units of the compact bone are called
Osteons
Name the blood vessel that enters through a hole in the center of diaphysis in a compact bone
Perforating canals (Volkman’s canals)
What factors contribute to the hardness and tensile strength of bone?
Hardness depends on crystallized inorganic mineral salts.
Collagen fibers and organic molecules provide tensile strength.
Why do you experience severe pain following a fracture?
Periosteum– part of a bone contains sensory nerves associated with pain
The process of bone formation is called osteogenesis, what is another term that also means process of bone formation.
ossification
endochondral ossification
method of forming a bone through an intermediate cartilage
involved in the formation of long bones
intramembranous ossification
forms the bone directly on the mesenchyme
involved in the formation of flat bones
Vitamin A
stimulates activity of osteoblasts.
Vitamin C
needed for synthesis of collagen
vitamin D
helps build bone by increasing the absorption of calcium from foods in the digestive canal into the blood.
Vitamins K and B12
needed for synthesis of bone proteins
IGFs
stimulate osteoblasts
promote cell division at the epiphyseal plate and in the periosteum
enhance synthesis of the proteins needed to build new bone
Thyroid hormones (T3 and T4)
promote bone growth by stimulating osteoblasts
insulin
promotes bone growth by increasing the synthesis of bone proteins
PTH
increases blood Ca+. Calcitonin from the thyroid has potential to decrease Ca+
Bone repair steps
Reactive phase
Fibrocartilaginous callus formation
Bone callus formation
Bone remodeling phase
Compound/open fracture
The broken ends of the bone protrude through the skin
Simple/closed fracture
Fracture does not break the skin
Comminuted fracture
The bone is splintered, crushed, or broken into pieces at the site of impact, and smaller bone fragments lie between two main fragments
Greenstick fracture
A partial fracture in which one side of the bone is broken and the other side bends; similar to the way a green twig breaks on one side while the other side stays whole, but bends; occurs only in children, whose bones are not fully ossified and contain more organic material than inorganic material.
Impact fracture
One end of the fractured bone is forcefully driven into the interior of the other.
Pott fracture
Fracture of the distal end of the lateral leg bone (fibula), with serious injury of the distal tibial articulation.
Colles fracture
Fracture of the distal end of the lateral forearm bone (radius) in which the distal fragment is displaced posteriorly.
effects of aging on bone tissue
demineralization, a loss of calcium from bones, which is due to reduced osteoblast activity
decreased production of extracellular matrix proteins (mostly collagen fibers), which makes bones more brittle and thus more susceptible to fracture.
