•Cells are enclosed by a plasma membrane
•Raw materials, energy, waste enter & leave only by crossing the membrane
•Eukaryote cells have an internal nucleus enclosed by nuclear membrane
•The cell membrane is a phospholipid bilayer with cholesterol & proteins, called a fluid
mosiac – because it is not rigid
•The cell membrane is selectively permeable
•Things cross the membrane by diffusion, osmosis, facilitated transport (all follow a
concentration gradient and don’t take energy), or active transport – movement against a
concentration gradient which requires energy
•Phagocytosis, pinocytosis, use of receptor proteins are other methods
•If the cell is hypotonic, (like when the body is dehydrated) it loses fluids thru its
membrane to the surrounding solution & shrinks, if hypertonic (like when the body is
bloated) the opposite happens
•isotonic means the same concentration as the surrounding solution
•Organelles are working units in the cell, and include the nucleus, ribosomes, rough and
smooth endoplasmic reticulum, golgi apparatus, lysosomes, perixosomes, vesicles, and
mitochondria
•Flagella, cilia, microvilli, centrioles are structures associated with the cell
•The nucleus is the part of the cell that contains the chromosomes
•Chromosomes are made up of DNA, humans have 23 pairs altogether, 22 of autosomes,
and one pair of sex chromosomes
•There are pairs because one is inherited from the father and one from the mother
•Areas of the chromosomes called genes hold the instructions for making specific proteins
– the genetic code
•Genes of the paired chromosomes are called alleles, can be alike (homozygous) or
different (heterozygous), one from the mother, one from the father; can be dominant or
recessive; affect appearance or function
•Nucleic acids store genetic information
•DNA is the abbreviation for DeoxyriboNucleic Acid – and it makes up genes that contain
instructions for producing RiboNucleic Acid
•RNA are the directions for making proteins
•Both are made of nucleotides that have a 5 carbon sugar, a nitrogenous base, and
phosphate groups
•DNA bases are adenine, thymine, cytosine, guanine - A-T C-G
•Genetic code is on one of the DNA strands, the other side holds it together
• 3 bases code for specific amino acids
• a strand of messenger RNA that is specific for the amino acid sequence of proteins is
formed on the DNA
•RNA bases are adenine, uracil, cytosine, guanine
•Messenger RNA passes through the nuclear membrane to bring the genetic information to
either ribosomes or rough endoplasmic reticulum for protein synthesis
•At the ribosome, transfer RNA matches the messenger RNA code and brings amino acids,
which become linked by dehydration synthesis to form proteins
•Proteins that get secreted go from the rough endoplasmic reticulum to the golgi
apparatus, where they are altered into the final product
•Lysosomes are membrane bound proteins that function in waste management
•Smooth endoplasmic reticulum functions in different ways - as storage containers for ions,
sites of detoxification, sites of lipid synthesis or break-down, depending on the cell’s needs
•Metabolism – the chemical reactions in the organism, either anabolism where molecules
get assembled into larger molecules that contain more energy – a process that requires
energy; or catabolism – larger molecules are broken down, which releases energy
•Energy is stored in ATP
•ATP – Adenosine TriPhosphate – has adenine, ribose, and three phosphate groups
•phosphate bonds store huge amounts of potential energy that is released when the bonds
are broken
•Then ATP becomes adenosine diphosphate (ADP) and inorganic phosphate
•Both proteins in the cytoplasm & the mitochondria make ATP from glucose break-down
•Mitochondria produce huge amounts ATP, and there are more in cells that require more
energy
•They are thought to originate from bacteria that became incorporated into cells many
millions of years ago
•Glucose's chemical formula is C6H12O6
•Glycolysis is a process that happens with enzymes in the cytoplasm
•Glucose is split into two 3 carbon molecules called glyceraldehyde-3-phosphate,
producing 2 ATP –
•It gets converted to pyruvate, then lactic acid if no oxygen is available
•High energy hydrogen ions and electrons are taken by nicotinamide adenine dinucleotide
(NAD)
•Pyruvate enters the mitochondria & is converted to acetyl CoA to enter the citric acid
(Krebs) cycle, that gives off CO2 & makes ATP and more NADH & a similar FADH2
•NADH & FADH2 bring hydrogens & electrons to the electron transport chain
•Concentration of hydrogen is higher in the outer compartment than in the matrix
•Molecules pass hydrogens through the electron transport chain into the outer
compartment
•Oxidative phosphorylation – hydrogens diffuse back into the matrix thru a protein that
uses the energy from diffusion to make ATP as they go into the inner compartment - makes
34 ATP and water from the rest of the glucose
•Fats & proteins can also be used for energy
•Fats carry more than twice the energy of carbohydrates
•Triglycerides are broken down to glycerol and fatty acids
•Glycerol can be converted to glucose or pyruvic acid
•Fatty acids become acetyl groups for citric acid cycle
•Proteins can enter after amine group is broken off
•Vitamins are important chemicals essential for normal function
•The body makes vitamin D in our skin
•Bacteria in the colon make vitamins K, B6, and biotin
•Fat soluble vitamins are absorbed if there is fat in the diet – vitamins A & E & D & K are fat
soluble
•Water-soluble vitamins are easy to absorb but are excreted rapidly in the urine, and all the
B vitamins are coenzymes in carbohydrate, nucleic acid, or amino acid metabolism
Bones, Muscles, Blood
•Skeletal System is made up of bones, the ligaments that bind bones together, and cartilage
•Bones are the hard elements of the skeleton whose function is to:
1.Support the muscles & soft organs
2.Interact with muscles
3.Protect delicate internal organs
4.Contain blood-producing cells
5.Store minerals like calcium & phosphate
•Parts of a long bone are the shaft (diaphysis) and ends (epiphyses)
•Compact bone makes up the periphery, spongy bone internally, and the cavity is filled
with yellow bone marrow (fat), except for a few places of red marrow (produces RBC’s &
WBC’s & platelets) the hip, sternum, ribs, skull, and epiphyses of the humerus & fumur
•Bone is covered with a periosteum membrane, epiphyses covered with cartilage
•Bone is hard because of extracellular calcium phosphate, which surrounds osteocytes
(bone cells)
•The cells are in spaces called lacunae that are arranged in osteons (Haversian system)
surrounding a central canal that carries blood vessels, canaliculi connect them
•Ligaments attach bone to bone, and are made of dense fibrous connective tissue with
collagen
•Cartilage has strands of collagen, and is smooth & flexible
•Fibrocartilage has bundles of collagen, and make up the intervertebral disks & menisci of
knee
•Hyaline cartilage has a glassy appearance, is found at articulations, & forms the embryonic
models of bone
•Elastic cartilage is most flexible and found in the ear & epiglottis
•Embryos have a hyaline cartilage skeleton, with chondroblasts surrounded by
perichondrium
•The perichondrium eventually forms a bony collar & the cartilage inside the bony collar
dies & becomes calcified - nutrients can’t diffuse through bone
•Blood vessels invade the calcified cartilage, osteoblasts enter & secrete osteoid proteins
and enzymes that help with the crystallization of extracellular calcium phosphate salts forming hydroxyapatite
•Grow in length occurs at the growth plate, which is stimulated by growth hormone
•Growth stops when sex hormone levels rise
•Ages 18 – females and 21 – males
•Osteoclasts remodel bone by dissolving hydroxyapatite & digesting osteoid, releasing
calcium & phosphate ions into the blood
•Shapes of bone change in response to mechanical forces – weight bearing exercises
increase overall bone mass & strength
•Osteoporosis – bones lose mass to release calcium to maintain body levels of calcium
•If there is low body calcium levels, parathyroid hormone stimulates osteoclasts to digest
bone, with high levels, calcitonin stimulates osteoblasts to make bone
•10 million Americans have osteoporosis
•1.5 million fractures/year
•Contributing factors include low calcium levels, estrogen decline, smoking, sedentary
lifestyle, underweight
•Steps in healing a fracture –
•A hematoma (blood clot) forms within hours, then a fibrocartilage callus fills in the space
within days, and is replaced by a bony callus within months, remodeled bone resembles
pre-fracture status after a year
•Bone classification is by shape:
•Long bones
•Short bones
•Flat bones
•Irregular bones
•206 bones in human body are divided into the axial & appendicular skeletons
•Skull has 2 categories:
•Cranial bones surround the brain: frontal, parietal, temporal, sphenoid, ethmoid, occipital
bone
•Facial bones: maxilla, palatine, vomer, zygomatic, nasal, lacrimal bones
•Mandible – the chin, hyoid bone – at top of neck
•Sinuses make the skull lighter, and develop shortly before and after birth as invaginations
from the nasal cavities
•The vertebral column supports the head, protects the spinal cord, attaches limbs
•33 vertebrae bones with spinous processes
•7 cervical
•12 thoracic
•5 lumbar
•5 fused sacrum
•4 fused coccyx
•Intervertebral disks
•12 pair ribs
•sternum
•The pectoral girdle (scapula and clavicle) attaches the upper extremity to the axial
skeleton
•Humerus - arm
•Radius, Ulna - forearm
•8 Carpals -wrist
•Hand has 5 Metacarpals & 14 Phalanges
•The pelvic girdle attaches the lower extremity to the axial skeleton, made up of the coxal
bones:
•Iliac crest
•Ischial tuberosity
•Pubic symphysis
•Femur – thigh bone
•Tibia & Fibula are the leg bones
•7 tarsals at the ankle
•Foot has 5 metatarsals & 14 phalanges
•Joints connect bones to each other and are sstabilized by ligaments & tendons
•Fibrous joints – immovable (skull sutures)
•Cartilagenous joints – slightly movable – intervertebral disks
•Synovial joints – freely movable and lined with a synovial membrane
•Examples of hinge joints are the knee & elbow
•Knee: fibrocartilage menisci deepen the joint on the tibia, cruciate ligaments cross inside
the joint between the tibia and fibula, and collateral ligaments hold it together on the sides
bursae protect tendons & reduce friction
•Examples of ball and socket joints are hip, shoulder
•Tendons are what attach muscles to bones
•A sprain is a partial tear to a ligament or tendon
•Bursitis is inflammation of a bursa that protects a tendon
•Tendinitis is inflammation of a tendon
•Arthritis is inflammation of a joint – osteoarthritis is loss of cartilage at the joint
•Muscles make up:
•40% of body weight males
•32% of body weight in females
•Includes skeletal, cardiac, and smooth muscle cells
•Muscles produce or resist movement, maintain blood pressure, generate heat
•Muscles cells are excitable and can contract & relax
•Skeletal muscles interact with skeleton & cause movement
•>600 skeletal muscles
•Work together as synergistic & antagonist groups – one side contracts while the opposite
side relaxes
•Attach to bones by tendons
•Muscles consist of groups of multinucleated muscle cells (fibers) and bundles of fibers are
called fascicles, enclosed in fascia sheath
•Fibers contain sarcomeres – segments between Z lines that attach actin microfilaments
•Myosin & actin microfilaments – made of protein – interact to cause muscle contraction
•Motor neurons stimulate muscle contraction by releasing acetylcholine (ACh) at the
neuromuscular junction
•ACh causes the membrane (sarcolemma), including indents called t-tubules, to depolarize,
allowing an influx of sodium ions, which causes the release of calcium ions from the
sarcoplasmic reticulum
•Calcium ions allow myosin to contact the myosin binding site on actin, form crossbridges,
split ATP, and swing, grab the next binding site, repeat; like pulling a rope - the ‘sliding
filament’ mechanism
•Troponin is attached to tropomyosin that is wrapped around the actin & hides the myosin
binding site
•Binding splits ATP bound on myosin into ADP & P, which then falls off the myosin so
another ATP scan take its place
•Muscles store enough ATP for 10 seconds of activity
•Creatine phosphate is a molecule that attaches phosphate to ADP for 30 - 40 more seconds
of activity
•Muscles need stored glycogen for a quick source of glucose (anaerobic – 2 ATP, forming
lactic acid)
•Aerobic respiration takes place in mitochondria, requires oxygen, and oxygen debt occurs
from build-up of lactic acid before aerobic kicks in
•Muscles will store more glycogen, develop more mitochondria and capillaries to bring
oxygen, if they are active all the time
•Fatigue - from lack of ATP
•Isotonic contractions – muscle shortens while maintaining a constant force
•Isometric contraction – force is generated & muscle tension increases but bones do not
move
•Motor neurons stimulate muscles by releasing ACh
•A motor unit consists of all the muscle cells that a neuron stimulates - an all or none
situation
•One action potential causes a muscle twitch
•Muscle tone is produced by an intermediate level of force, causing some fibers to contract
•Increasing force recruits more motor units
•After stimulation and contraction there is a latent period where the membrane repolarizes
and calcium transports back
•Additional stimuli cause greater force
•An increase of force by an increase of rate of stimulation is summation
•Too much summation with no relaxation is tetanus – sustained contraction – that leads to
fatigue
•Rigor mortis – myosin can not unlock from actin
•Slow twitch muscles contract slowly, use aerobic metabolism – have many mitochondria &
blood vessels, little glycogen, store oxygen in myoglobin – body posture
•Fast twitch muscles contract more quickly, have fewer mitochondria, store glycogen, need
creatine phosphate & anaerobic metabolism, are unable to sustain long contractions (but
can use aerobic mechanism too) – used for quick movements
•Strength training builds more myofibrils, glycogen and creatine phosphate storage
capacity
•Aerobic training - increases capillaries, mitochondria, myoglobin
•Involuntary muscle types:
•Cardiac – cells are connected by intercalated discs, rhythm set by pacemaker cells – make
up the heart
•Smooth muscles – joined by gap junctions – make up walls of the guts and blood vessels
•Myasthenia gravis – destroys acetylcholine receptors on skeletal muscle cells
•Muscular dystrophy – abnormal dystrophin protein allows calcium to leak into muscle
cells
•Tetanus – bacterial toxin overstimulates the nerves controlling muscle activity, especially
jaw & neck muscles, causing sustained contraction
•Muscles of the Body
•Facial expression: frontalis, zygomaticus major, orbicularis oris, orbicularis oculi,
depressor anguli oris
•Back: trapezius, latissimus dorsi, erector spinae
•Chest and abdomen: pectoralis major, serratus anterior, external oblique, rectus
abdominus
•Upper extremity: deltoid, biceps brachii, triceps brachii, brachioradialis
•Lower extremity: gluteus maximus, sartorius, quadriceps, tibialis anterior, hamstrings,
gastrocnemius