Definitions Flashcards
Homeostasis
The ability of the body to maintain relatively constant internal conditions
Example:
In terms of body temp, blood pressure, blood glucose, water balance, pH
Organic Compounds
Contains Carbon-Carbon bonds
Ex:
Sugars, proteins, fats
Inorganic Compounds
do not contains Carbon-Carbon bonds
Ex:
Water, oxygen, table salt (NaCl)
Enzyme
Substances that speed up chemical reactions, but are not consumed in the process
- almost like protein
- each enzyme catalysts a specific reaction
- they only speed up the reaction
ATP
(Adenosine Triphosphate)
Consists of the nitrogenous base “A”, a sugar (ribose), and 3 phosphate groups
- the immediate most direct energy source for our cells
- calls can’t use glucose directly, instead they transform glucose into numerous ATP
-glucose –> mitochondrion –> ~36 ATP
Peptide Bond
A group of 4 covalently bonded atoms that links 2 amino acids in a protein or other peptide.
-joins the OH of one amino acid to the H of another amino acid and releases H2O
H H O
l l ll
H-N--C--C-OH
l
R
Acid
An H+ donor
A compound that releases H+ into solution
Base
A compound that can remove H+ ins from solution
Phospholipid
An amphipathic molecule composed of 2 fatty acids and a phosphate-containing group bonded to the 3 carbons of a glycerol molecule.
-composes most of the molecules of the plasma membrane and other cellular membranes.
Hydrophobic
Pertaining to molecules that do not attract water or dissolve in it because of their nonpolar nature
-such molecules tend to dissolve in lipids and other nonpolar solvents
Simple Diffusions
The movement of a substance from an area where it is highly concentrated to an area of lower concentration.
-it’s caused by random molecular motion and happens automatically
Osmosis
The diffusion of water across a selectively permeable membrane toward and area of high solute concentration.
Active Transport
Uses ATP energy to actively pump salutes across the membrane against their concentration gradient.
-closer to facilitated diffusion
Microvilli
Densely packed, short, non-movable extensions
-greatly increase the surface area of the cell
Cilia
Longer extensions of the cell membrane that beat in a rhythmic fashion.
Mitochondrion
Major site for cellular respiration
- where ATP is formed by metabolizing glucose using O2
- cells with higher energy demands contain more mitochondria and the cells that need greater energy can add more mitochondria.
Ribosomes
Sites where proteins are synthesized from amino acids
-they float freely in cytosol or are attached to the ER
ER (Endoplasmic Reticulum)
A system of tubes running throughout the cell and continuous with the nuclear membrane
RER and SER
Mitosis
Original nucleus divides to produce another genetically identical to itself
-technically not cell division but the division of the nucleus.
Simple squamous epithelial tissue
a) flat shape makes it ideal for the rapid diffusion of substances.
b) provides smooth surface to reduce friction
Pseudostratified columnar
Secretion and movement of mucus; had cilia and goblet cells
Gap junction
a) cells are held together by interlocking protein called connexons
b) the connexon has a hollow space through its center that allows small molecules and ions to pass directly from cell to cell
Mesenchyme
a) arises early in embryonic development
b) eventually gives rise to all the other CT types
c) some sticks around in mature tissue to regenerate damaged tissues
Areolar Connective Tissue
a) “syrupy” ground substance
b) may contain all 3 fiber types (collagen, reticular, and elastic) loosely arranged
Functions:
- soft packing material
- reservoir of water and salts
- plays an important role in inflammation
Keratinocytes
a) most common cell type in epidermis
b) these cells make the fibrous protein keratin
c) tightly joined to each other by desmosomes
Stratum Corneum
a) consists of dead keratinocytes
b) protects deeper skin from abrasion and infection
c) limits water loss from the skin
Stratum Basale
a) a region of active mitosis that produces new skin cells
- gets new epidermis every 30-40 days
b) newly formed keratinocytes die as they get too far from the dermal blood supply
c) other cell types found in the stratum basale
- melanocytes=skin color
- tactile cells=sensative
Melanocyte
a) produces the pigment melanin
b) melanin is then transferred to neighboring keratinocytes which concentrate the pigment on the “sunny” side of their nuclei
Dendrite cell of skin
A macrophage (wbc) that detects pathogens and toxins
Sebum
a) an oily substances secreted by sebaceous glands that softens and lubricates the hair and skin
b) has antimicrobial properties
c) these glands are usually associated with hair follicles
Compact bone
a) makes up outer surface of bone
b) richly vascularized
c) heavy
d) found where stress loads are large and come mainly from one direction
Spongy Bone
a) found in center of bones
b) not directly vascularized
c) much lighter than compact bone
d) found where there are weak-moderate stresses coming for multiple directions
Sesamoid bone
Bones that are formed within the tendons in response to mechanical stress
Hydroxyapatite
a) makes bone hard
b) the calcium phosphate interacts with other calcium salts to form these crystals
c) if bone just had these crystals of hydroxyapatite, it would shatter easily.
Osteoblasts
a) bone-building cells
b) connect to each other via gap junction
c) once ossification is complete, the osteoblasts become “trapped” in the lacunae and transform into osteocytes
Osteocytes
a) mature bone cells that maintain the tissue by recycling Ca2+ salts
b) exchange nutrients with their neighbors via gap junctions
c) participate in fracture repair
Osteoclasts
a) “bone destroyer”
b) secretes acids/enzymes that break down the matrix
c) very large cells derived from wbc’s
Periosteum
Dense irregular CT that wraps the outer surface of bones
a) osteoblasts on the inner surface of the periosteum secrete the bony matrix
b) tendons attach to the periosteum
Osteon
The fundamental building blocks of compact bone
Osteoporosis
a) refers to a group of diseases in which bone is degraded faster than it can be rebuilt
b) very low bone density
c) the bone becomes porous and more susceptible to fractures
d) especially prone to compression fractures and broken hip
e) can occur in either sex but is especially coon in postmenopausal women because at menopause, the ovary secretes less estrogen; thus, less of a stimulus for bone grow
f) it can occur in female athletes who have very low body fat (adipose tissue)
Symphysis
A joint in which two bones are held together by fibrocartilage
Synovial joint
Joint in which the bones are enclosed in a capsule filled with fluid
Most joints in the body are synovial
Meniscus
Pad of fibrocartilage that improve the fit between the bones
Increases stability of joint
