anatomy final

free radical

unstable molecule/ atom , has an unpaired electron and is highly reactive

atoms

typically stable when their outer electron shell is full. (8 electrons) this is why atoms tend to gain, lose and share electrons

ionic bonds

an atom gives away one or more electrons to another atom

covalent bonds

sharing of electrons between 2 atoms. shares pairs of electrons

hydrogen. bonds

weakest bond. weak attraction of hydrogen atoms to a more electronegative atom

atomic number

represents PROTONS in an atom, determines the elements identity (ex: hydrogen has atomic number of 1 )

mass number

SUM of protons and neutrons in nucleus: represents atoms total mass

mass weight

average mass of all isotopes of an element, weighted by their natural abundance. often slightly different than mass number

negative feedback

body responds to a change in homeostasis by reversing the change back to normal condition. maintains stability and homeostasis

ex: body temp, blood sugar regulation, blood pressure regulation, water balance

positive feedback

a mechanism where the body amplifies a change, pushing forward a process until its completed

ex: childbirth, blood clotting, breast feeding

what is the plasma cell membrane made of

phospolipid bi-layer, proteins, cholesterol, carbohydrates

phospholipids

make up basic structure of plasma cell membrane. hydrophillic heads outward hydrophobic tails inward

proteins

scattered through the plasma membrane like tiny workers, some span the entire membrane

cholesterol

glue that holds the membrane together, ensures flexibility and stability

carbohydrates

name tags of cells, recognizes other cells to communicate. attatched to proteins/lipids. form glycoproteins or glycolipids

transcription

NUCLEUS DNA→mRNA

mRNA carries genetic info to ribosomes

to create a working copy of DNA instructions that can leave the nucleus

translation

CYTOPLASM mRNA→tRNA (amino acids) protein synthesis, where ribosomes read the mRNA and assemble amino acids into a protein

purpose of DNA replication

important to ensure every new cell has an exact copy of the genetic material essential for

growth

repair

reproduction

maintaining genetic continuity

4 main tissue types

epithelial tissue , connective tissue, muscle tissue, nervous tissue

epithelial tissue

covers and lines surfaces, like skin and internal organs

connective tissue

supports, protects, connects, (bone, blood, fat)

muscle tissue

enables movement, found in muscles like skeletal, cardiac, smooth

nervous tissue

sends and receives signals found in brain , spinal cord and nerves

epithelial tissue subtypes

simple squamous,

simple cuboidal ,

simple columnar,

stratified squamous,

transitional epithelium

pseudo stratified columnar

simple squamous is found where

air sacs of lungs, lining of blood vessels (endothelium)

where is simple cuboidal found

kidney tubules, glands

where is simple columnar found

digestive tract lining (non-ciliated), uterine tubes (ciliated)

where is Stratified squamous found

skin (keratinized), mouth/esophagus (non-keratinized)

where is Pseudostratified columnar found

trachea, upper respiratory tract

Transitional epithelium:

urinary bladder

3 layers of skin

epidermis, dermis, hypodermis

epidermis function

protection, water proofing, UV defense

dermis function

strength, elasticity, sensory, thermoregulation,

hypodermis function

insulation, energy storage, anchors skin

how epidermis aids in water conservation

stratum corneum prevents water loss with keratin and lipids

how does dermis aid in water loss

contains sweat glands for cooling, blood vessels constrict and dilate to retain/release heat and contains oil/sebaceous glands

how does hypodermis aid in water conservation

adipose tissue insulates and stores energy reducing heat loss

sub layers of epidermis

stratum basale

stratum spinosum

stratum granulosum

stratum lucidium

stratum corneum

spongy bone

porous,

looks like honey comb, absorbs shock

ends of long bones and inside short/flat and irregular bone.

makes blood cells

compact bone

dense, hard, smooth

tightly packed bone cells

provides strength and rigidity

located in outer layers of all bones

osteoblasts

bone building cells

develop osteogenic stem cells and secrete osteoid (unmineralized bone matrix) over time

calcium + phosphate deposit into osteoid making it into hardened bone tissue

osteoblasts during growth

add new bone matrix, helping bones grow longer and wider

osteoblasts during repair

rebuild bone after fractures by producing new bone tissue

osteoblasts during remodeling

continuously lay down new bone to replace old/damaged bone

osteoclasts

bone resorbing cells

large multi-nucleated cells that break down bone tissue.

releases enzymes and acids that dissolve mineralized matrix (bone resorption)

osteoclasts during growth

osteoclasts remove bone from inner surface, shaping medullar cavity

osteoclasts during repair

clear away damaged bone so osteoblasts can rebuild

osteoclasts during remodeling

break down old or unnecessary bone to maintain bone strength and calcium balance in blood

bone repair process order

hematoma formation → fibrocartilingous callus formation → bony callus formation → bone remodeling

what happens in hematoma formation

parathyroid hormone

INCREASES blood calcium by breaking down bone

stimulates bone resorption by increasing osteoclast activity

Calcitonin (vitamin D)

Increases calcium absorption in the gut, supports bone remodeling and mineralization

calcitonin

LOWERS blood calcium by storing it in the bone

inhibits bone resorption, supresses osteoclast activity

effects of aging

bone density decrease

osteoblast activity slows

more bone is broken down that rebuilt → risk of osteoporosis

hormones like PTH and calcitriol stay active, but bone is slower to rebuild.

what happens in hematoma formation

occurs immediately after the fracture (within a few hours)

(blood clot) forms at the fracture site and helps stop the bleeding.

stabilizes the break

brings in cells and growth factors to start healing

*triggers inflammation which helps clear out dead tissue

what happens in fibrocartiligineous callus formation

(few days after- lasts 2-3 weeks)

a soft callous forms around the break to connect bone ends

fibroblasts and chondroblasts move in and produce soft cartilage like tissue

soft callus isnt strong yet but acts as a temporary bridge for next stage

what happens in bony callus formation

(starts at 2-3 weeks, lasts for months) - soft callus turns into hard, bony callus

osteoblasts create spongy bone through a process called endochondral ossification

the new bone is stronger than the soft callus, but still not as strong as normal bone

bone remodeling

(months-years)

bony callus is reshaped into strong mature bone

osteoclasts remove extra or misaligned bone, osteoblasts rebuild bone in correct shape + direction

bone adapts to stress and movement, making it strong and functional again

afferent

carries signals from sensory body to CNS

efferent

carries signals from cns to sensory body

what receptor at NMJ

nicotinic

sympathetic nervous system area

thoracolumbar region of the spinal cord

parasympathetic nervous system area

craniosacral region of the spinal cord

somatic originates where

in the whole spinal cord

what does troponin bind to

calcium ions to initiate muscle contraction.

calcium influx

triggers ACh release from vesicles

what happens after calcium binds to troponin

causes tropomyosin to expose myosin binding sites on actin, triggering AP

what does preganglions in parasympathetic release

acetylcholine - binds to nicotinic receptors

post ganglions in parasympathetic

release ACH-

binds to muscarinic receptors

initiates rest and digest

preganglions in sympathetic nervous system

binds to nicotinic receptors on post ganglion

post ganglion in sympathetic

release norepinephrine which binds to adrenergic receptors to initiate fight or flight responses.