Midterm unit 3 Flashcards
Integumentary system
The skin: it protects, prevents water gain or loss, megablov regulation, immune function, temp regulation, sensory receptor
What area the 3 skin layers
epidermis, dermis, subcutaneous
Keratinized Stratified Squamous Epithelium
a type of stratified epithelium that contains numerous layers of squamous cells, called keratinocytes, in which the superficial layer of cells is keratinized. This type of epithelium comprises the epidermis of the skin.
Keratinocytes
produce keratin a tough fibrous protein that produces protection. Most abundant and found in all Epidermis strata. These divide to generate new on that replace dead ones shed from surface. They can twist and intertwine forming helian intermediate filaments of sytosketaton. They can also form cytokeratin which gives skin its strength and makes epidermis water resistant
Keratin
a tough fibrous protein that produces protection. Most abundant and found in all Epidermis strata. These divide to generate new on that replace dead ones shed from surface. They can twist and intertwine forming helian intermediate filaments of sytosketaton.
Melanocytes
produces the pigment melanin that protects against damage by UV. These are long and branching they are found among keratinocytes. Produce and store melanin. Transfers melatonin through melanosomes. Tanning is a result of melanocytes producing melanin to clock UV light from causing mutation to keratinocytes and fibroblasts.
-Inside the melanocytes are melanin
Tactile cells
Touch receptor cells, change shape with pressure(few in number, stratum basale, when compressed send signals to nerve endings) Found scattered
Dendrite cells
Used in immunity
Kernelization:
When the Keratinocytes synthesize significant amounts of protein keratin. Causing nucleus and organelles to disingrate which leads to death.
Layers in Epidermis
-Stratum Basale
-Stratum spinous
-stratum granulosum
stratum Lucidum
-stratum corneum
Stratum Basale
deepest layer. Cell division and creation of other layers. Single layer of low columnar cells attached by hemidesmosomes. There are 3 types of cells that are occupied in this Keratinocytes, Melanocytes, tactile.
Stratum Spinosum
a layer of 8-10 keratinocytes and some denertic cells form this. Creating new cells pushing them to the surface which then attaches them desomosomes, providing structural support for cells. They look spiny. Contains the Epidermal dendric Cell.
Stratum Lucidum
s only present in thick skin finger tips, palms, soles. Thin translucent layer that is superficial to the stratum granulosum. These are flattened and pale. Filled with a protein called eleidein which is an intermediate product of keratin formation.
Stratum Granulosum:
The non diving cells of the stratum granulosum are filled with granules of keratin. 3-5 layers of superficial stratum spinosum. This begins with the process called keratinization. Which leads to cell death.
Stratum corneum
is always outermost, composed of 20 layer cell remanence. Hornlike layer. Dead keratinocytes are anucleate (lacking nucleus). They hav large amounts of Keratin. This is where the dead cells shed and secrete.
Thick Skin
found in palms, hands, and feet. Epidermis of thick skin is 0.4 mm-0.6 mm. Houses sweat glands but no hair or oil glands
Thin Skin
Lacks stratum lucidum. Contains hair follicles, sebaceous glands, and sweat glands. Epidermis is between 0.075 mm- 0.150
Dermis
Composed of CT and primarily collagen fibres but have elastic and reticular fibres aswell (this is the second layer)
What is all found in the dermis
blood vessels, sweat glands, sebaceous glands, hair follicles, nail root, sensory nerve, smooth muscle tissue.
2 regions in the dermis
-Papillary, reticular
Papillary region
-consists of areolar CT with capillaries tactile receptors free nerve ending
-Is deep to the epidermis
-monitors sensory and touch
-tactile receptors
Reticular Region
-Dense irregular CT with adipose cells, hair follicles, nerves, glands
-Even deeper then papillary
Subcutaneous layer
-areolar CT and Adipose CT
-stabilized and binds skin
-acts as energy
-attached the skin to underlying tissue and organ
Provides thermal insulation
-drugs are often injected here
Hair
anugo: a fine unpigmented downy hair that first appears on the fetus in last trimester
Vellus: Replaces when at birth lightly pigmented found in upper and lower limbs
Terminal: course, pigmented. Grows on scalp eye brow and lash, pubic, and face.
nails
-Composed hard keratinized epidermal cells located over the dorsal surfaces of the ends of fingers toes
-appear pink because of the blood flow underneath
Skin Glands:
-secret oily substance called sebum which prevents dehydration of hair and skin inhibits growth of certain bacteria
-simulated by androgen
Sweat glands
-located reticular portion of dermus
-both contain myoepithelial which are specialized epithelial cell that are sandwiched in basement membrane this is squeezed which causes secretion
Merocrin glands:
- For cooling the body, secretes watery solution to cool body and eliminate waste
-main function is thermoregulation
-watery
Apocrine glands
- located mainly in the skin of the axilla, groin, areolae, and bearded facial regions of adult males. This happens during sex.
-good nutritious stuff
-release secretion into hair around nipples, pubic, anal region.
-colling body
-or stress
-bacteria is the smell
-emotional
Sebaceous Glands
-produce oily waxy secretion called sebum which is discharged into hair. Which acts as a lubricant on the skin to prevent dry and brittle and cracks
Sebum
helps moisturize and protect the skin.
4 steps in wound healing
1) Cut blood vessels and bleed into wound Blood brings clotting proteins, numerous Leukocytes blood vessels and antibodies.
2) Blood clot forms, prevents continuation. As well as prevents bacteria, stops exposure.
3) Blood vessels grow and granulation tissue grows. It becomes granulation tissue which is a vascular CT.
4) Epithelium regenerates and a scab is made Replaced by fibrosis
Regeneration of skin
replacement of damaged cells with same type
Fibrosis of skin
replaces with different cells produce scar tissue.
First degree burn
only the epidermis mild pain no blister or loss of skim function
second degree burn
destroy the epidermis and part of dermis, some skin is lost. Redness, blister, edema, and pain
3rd degree burn
Full thickness burn into subcutaneous. Most functions are lost and region is numb
What causes difference inn skin colour
-hemoglobin, melanin, carotene
Hemoglobin
oxygen binding protein present in red blood cells. Gives red blood cells the colour. If blood vessels diameter increase red tone is seen.
Melanin
- Eumelanin: shades of brown and black
- Pheomelanin: lighter shades of tan, yellow and red.
-transferred in melanosomes from melanocytes to keratinocytes
Carotene
yellow-orange pigment. Found in veggies. Inside the keratinocytes in the stratum corneum and subcontneus fat. May improve immunity cell number and activity.
what makes someone skin darker
melanocytes produce relatively more and darker melanin than lighter skinned individuals. Active melanocytes tend to package melanin into cels in the more superficial epidermal layers
Dermal blood vessels of the dermis do what
provide nutrients to the skin and help regulate body temp
Vasoconstriction
the diameter of the vessels narrow so relatively less blood is transported through them. This occurs to produce heat.
Vasodialation
diameter of vessels increases. More blood can be transferred through them. This occurs to release excess heat.
Functions of Subcutaneous layer
helps provide insulation, regulate temperature, and store fat.
Vitamin D synthesis
Keratinocytes convert a steroid molecule to Vit D, which then releases to the blood and converts to calcidiol (kidney converts it), DBP transports to organs increasing absorption of calcium and phosphate.
Regions of the bone
Periosteum Medullary cavity Endosteum Diaphysis Epiphysis Metaphysis Articular cartilage
effects of Again on the skin
Wrinkles: fewer fibro blasters, decreased collagen and elastic fibres
Dehydration and cracking: reduced sebaceous gland activity
Sweat production increases
Decrease in function melanocytes grey hair, atypical skin pigment
Subcutaneous fat is lost general decrease skin thickness
-More brittle nails
-Migration of cell is slow- repair delayed
-increased susceptibility to pathological conditions
Periosteum
A tough sheath of dense irregular CT, protects the bone from surrounding structure, anchors blood vessels, and nerves to surface of the bone and is an attachment site for ligaments and tendons.
Fibrous layer of Periosteum
The outer layer of dense, irregular CT on the outside of bone
Cellular layer of periosteum
includes osteoprogenitor, osteoblasts, and osteoclasts that produce growth of bone matrix
Medullary Cavity
A space that contains fatty yellow bone marrow in adults. is a cylindrical space within the diaphysis that contains red bone marrow which is replaced with yellow bone marrow when adults
Endosteum
membrane that lines the medullary. A thin layer of osteoprogenitor cells, blasts, and clasts that is active in growth and repair
Diaphysis
elongated usually cylindrical diaphysis is leverage and major weight for a long bone. The shaft. Composed of compact bone while spongy bone extends internally from this compact bone in spicules (thin needle like)
Emphasis
from the distal and proximal end of a long bone. Composed of an outer thin layer of compact bone and an inner more extensive region of spongy. Covering joint surface with hyaline cartilage called articular cartilage
Metaphysis:
are the area where epiphysis and diaphysis join. In a goring bone this region has epiphyseal plate. (is a line for adults)
Articular cartilage
thin layer of hyaline cartilage covering the epiphysis of long bones. Absorbs shock and stops friction.
cells of bone tissue
Osteoprogenitor cells Osteoblasts Osteoclasts Osteocytes
Osteoprogenitor cells
unspecialized bone cells located in both periosteum and endosteum. They go through a dividing process called cellular division and produce osteoblasts
Osteoblasts
Perform the important function of synthesizing and secreting the initial semisolid organic form of bone matrix called osteoid. After producing and secreting they differentiate into osteocytes.
Osteocytes
These are formed from osteoblasts that have lost their bone-forming ability when enveloped by calcified osteoid. They maintain bone matrix and detect stress which then inform osteoblasts and may lead to deposition of new bone matrix
Osteoclasts
derived from fused bone marrow cells. They are involved in breaking down bone restoration.
Red Bone marrow
-Hemopoietic (blood cells forming)
-Contains reticular CT, developing red cells and adipocytes
-Found in spongy
Adults: located in portions of the axial skeleton, in proximal epiphyses of humerus and femur
Children: located in spongy bone of most bones and medullary cavity of long bones
(found in skull, ribs, spine, pelvis
Yellow bone marrow
product of red bone marrow degeneration in adults, fatty substance, may convert back to red bone marrow. (found in jaw, shoulder, arms, legs)
Spongy bone
Lamellae are arranged in a lattice of thin columns called trabeculae. They lack osteons.
Trabeculae
a small, often microscopic, tissue element in the form of a small beam, strut or rod that supports or anchors a framework of parts within a body or organ. Found in Spongy bone.
Compact bone is composed of:
Osteons
Concentric lamellae Interstitial lamellae Lacunae
Canaliculi
Central canal
Perforating canals
Osteons
a cylindrical structure found in compact bone tissue. The osteon provides strength and support to the bone, and it also helps in the repair and remodeling of bone tissue.
Concentric lamellae
rings of bone connected to tissue that surrounds canal. Each contains collagen fibres. Gives bone strength and resilience.
Interstitial lamellae
help “glue”, or anneal haversian systems to one another – this arrangement is important in maintaining cortical integrity. They are leftover parts of osteons.
Lacunae
small spaces that house each Osteocyte
Canaliculi
tiny channels through the lacunae and centeral canal.
Central Canal
channel that lies in the center of osteon and runs parallel, blood vessels and nerves.
Perforating canals
contain blood vessels and nerves, and run perpendicular to central cells.
Ossification (bone growth) (replacement)
1) Ossification enters form within thickened regions of mesenchyme
2) osteoid undergoes calcification
3) Woven bone and surrounding periosteum form
4) Lamellae bone replaces woven bone
Endochondral ossification (growth replacement of hyaline)
- Fetal hyaline cartilage develops
- cartilage calcifies and a perosteal cone forms
- Primary ossification forms in the diaphysis
- secondary ossification forms in the epiphyses
- Bone replaces almost all cartilage exert the articular cartilage and epiphyseal cartilage
- Lengthwise growth continues until the epiphyseal plates ossify and form epiphyseal lines
The epiphyseal growth plate and growth line
-a growing long bone that is calcified and replaced by bone
Bone matrix formation
osteoblasts secrete osteoid. Calcification occurs, calcium ions and phosphate ions reach critic levels for clarification
Bone matrix Respiration
matrix is destroyed by substance released. Liberated calcium and phosphate ions enter blood and then blood calcium levels low.
Activation of Vit D to Calcitriol
- Light converts keratinocytes to Fit D which releases ti blood
- Vit D passes through liver turns into calciciol
- Calcidiol circulates blood. Then converted too Calcitriol
Calcium Homeostasis
stimulus: Low blood calcium levels
Receptor: Parathyroid glands detect low blood calcium levels
Control Centre: Parathyroid glands release parathyroid hormone
Restored: Blood calcium rise and return to a normal homeostasis
Stress fracture
thin break caused by increased physical activity
Pathological fracture
weakened by disease
Simple fracture
broken bone does not penetrate through the skin
compound fracture
broken bone breaks the skin
Steps to bone repair
- Fracture hematoma forms
- Fibrocartilaginous callus forms
- a hard bony callus forms
- the bone is remodelled
General functions of the bone
support and protection, levers for movement, hematopoiesis (blood cell production), Storage for mineral and energy reserves
