RAT 9 Flashcards
What are the accessory structures of the integument? From which tissue type are they derived?
- hair nails and glands
- epithelium
What are some functions of human hair?
Protection Sensation Thermoregulation
What tissue composes hair?
Squamous keratinzed epithelial cells
What are the two parts of a hair?
Shaft, Root
Are there any cells in the shaft still living?
No
Which part of the hair undergoes mitosis?
Matrix
What is the hair follicle?
An infolding of the epidermis in which a hair is embedded in the skin
In a transverse section, what are the three regions of a hair?
Inner Medulla, Middle Cortex, Outer Cuticle
What is the smooth muscle that attaches to a hair follicle? What does it do?
- arrector pili
- attach to the dermal root sheath on one end and the dermal papillary on the other end
Describe the three types of hair?
Lanugo: fetus has a thin, nonpigmented type covers the whole body
Terminal Hair: thicker, coarser, and pigmented
Vellus: thinner, nonpigmented
What pigment largely determines hair color?
Melanin
Nails are composed of what type of tissue?
Stratified Squamos Epithelium
What sits on top of the epidermal nail bed?
Nail Plate
What is the nail body?
Portion you can see
Nail Root
Under the skin
Nail Matrix
Contains actively dividing cells
What is another term for cuticle?
Eponychium
Where does nail growth occur?
Nail Matrix
Lunula
Opaque region near the proximal nail fold
What are some important functions of nails?
- safeguard underlying tissue
- better gripping
What are the two basic types of glands?
- sweat
- sebaceous
What is an alternate term for sweat gland?
Sudoriferous
What is merocrine secretion?
Released by glands via exocytosis
What is the most prevalent type of sweat gland? Describe the structure, secretion, and function of this type of gland.
- simple, coiled, tubular glands in the dermis
- exits through a tiny sweat pore in epidermis
- thermoregulation
Where are apocrine glands located? When does this gland become active? Why does it lead to body odor?
- armpits, anal, areolae
- influenced by sex hormones
- metabolized by bacteria, creating odor
Where are ceremonious glands located? What do they produce? What is the function?
- ear
- cerumen
- lubrifayes tympanic membrane, traps incoming particles
Where are mammary glands located? What do they produce? What is the function?
- milk
- nourish infants
Where do sebaceous glands typically release their product? What do they produce? What is the function?
- hair follicles
- sebum
- keep skin moist, kills certain bacteria/deter growth
What type of secretion is used by sebaceous glands?
Holocrine
What is another name for bone tissue?
Ossetian
Osseous Tissue
Is each bone in your body an organ?
Yes
Important Functions of Bones
- protection
- mineral storage and acid base homeostasis
- blood cell formation
- fat storage
- movement
- support
What are five general bone shapes?
Long Bones (humerus)
Short Bones (carpals)
Flat Bones (most runs of skull, ribs)
Irregular Bones (vertebrae)
Sesamoid Bones (patella, kneecap)
Do all bones have a diaphysis? Epiphysis? Medullary cavity?
Only long bones
What is diploe?
Spongy bone tissue of flat bones
Name two sources of blood to bone
Nutrient Artery: long bones
Epiphyses
What is a nutrient foramen?
What nutrient arteries enter the bone
What is red bone marrow?
Consists of a network of reticular fibers, supporting islands of blood forming hematopoietic cells
What is yellow bone marrows?
Stores triglycerides, contains mostly of blood vessels and adipocytes
In adults, where is yellow and red bone marrow found?
Yellow: essentially everywhere
Red: pelvis, proximal femur and humerus, vertebrae, ribs, sternum, clavicles, scapulae
How is osseous tissue similar to other connective tissues?
Mainly of extracellular matrix with cells scattered throughout
What happens to a bone if the organic component of the matrix is deficient?
Bone becomes flexible and unable to resist compression
What cells give rise to osteoblasts?
Osteogenic Cells
What is the primary function of osteocytes? Where are they located?
Secrete chemicals that are required for maintaining the ECM
What is the primary function of osteoclasts?
Bone resorption; they break down the bone ECM
What is the functional unit of compact bone?
Osteon
What are the layers that compose compact bone?
Lamellar
What is the center of each osteon?
- central canal/Haversian canal
- blood vessels and nerves
What are the small cavities found in compact bone? What cells reside in them?
- lacunae
- osteocytes and lacunae
What small channels connect the lacunae?
Canaliculi
What is a perforating canal?
Central canal of neighboring osteons are connected by a second type of canal
What are some important functions of spongy bone?
forms a protective framework for the bone marrow
What are the branching structure found in spongy bone?
Trabeculae
What are some structures found in compact bone that are not found in spongy bone?
No central or perforating canals
Name two bones for bone formation.
Ossification, Osteogenesis
What are the two types of classification?
Intramembranous
Endochondral
What is the term for the immature bone that forms first? Describe its structure
- primary bone/woven bone
- irregularly arranged collagen, bundles, abundant osteocytes, and little inorganic matrix
What is the term for the mature bone that replaces immature bone? Describe its structure.
- secondary bone (lamellar bone)
- fully formed lamellae with regularly arranged collagen bundles that are parallel to one another
Which bones form via intramembranous ossificiation?
Primary bone
Where does this type of bone formation take place?
Mesenchymal membrane
Which bones form via endochondral ossifications?
All bones below the head (except the clavicle)
Where does this type of bone formation occur?
Hyaline cartilage
What is the epiphyseal line? What does the presence of the epiphyseal line indicate?
- a calcified remnant of the epiphyseal plate
- the long bone can no longer grow in length
What is the term for growth in width?
Appositional Growth
Where does this primarily take place? How does this impact the lamellae?
- between the periosteum and the bone surface
- new lamellae are formed
What process occurs at the same time in the medullary cavity?
Osteoclasts digest the inner circumferential lamellae
What is bone remodeling? What two process does it involve?
Continual process of bone growth and bone less that takes place within healthy bone
- bone desposition
- bone resorption
When does bone remodeling occur?
Continously
What cells lead to bone deposition and bone resorption?
Bone disposition: osteoblasts
Bone resorption: osteoclasts
When does bone deposition outpace bone resorption? When are the two roughly equal?
- childhood
- in young adults
What will lead to increased bone deposition?
Stress, tension, pressure
Why do braces allow an orthodontist to straighten a person’s teeth?
When continuous pressure is placed, osteoclasts are stimulated and bone resorption occurs
What is the impact of testosterone on bones? Estrogen?
T: promotes bone deposition
E: depresses osteoclast activity
What is the primary effect of vitamin D in the body?
Bones
What homeostatic mechanisms occur if the blood calcium ion level decreases below the normal range?
Bone deposition won’t take place
What homeostatic mechanisms occur if the calcium ion level is too high?
Thyroid releases calcitonin, decreases reabsorption of calcium by the kidneys
