What i learned in Anatomy & Physiology Year 1 by 2102772

Homeostatic

21702772 — 2017-12-10 02:29:54 UTC

Homeostatic is about cell preserving itself in a stable range of internal environment, irregardless or in response to external environment commonly through homeostatic regulation (negative feedback mechanism (positive). It regulates osmolarity, glucose, water, temp bp and salts level etc.. It requires 1)receptor 2) control center 3) effector. It allows protein to function in an optimal condition.

Denaturation

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changes in ph or temperature above/below its range limit will cause protein in its tertiary or quarternary form to denature (changes in shape) rendering it unable to perform its function. However this process is reversible upon normal condition. Deaths occurs at temperature above 43C and get tagged by ubiquitin

Organ

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Organ is composed of at least 2 primary tissues working together for a specific function

Organ system

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organs with related function may be group together into organ system

Organism

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cell tissues and organs work together to maintain homeostasis as a single organism

polysaccharide

21702772 — 2017-12-10 14:39:52 UTC

monosacharide are single unit such as glucose, 2 becomes dissacharide, large molecule- polysaccaharide- plant (celluose, starch), animal (glycogen)

Triglyceride

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Dehydration synthesis between glycerol and fatty acid produce glyceride, diglyceride and triglyceride depending on no. of FA

Protein

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Amino acid sequence is known as protein when it exceeds >100 a.a. <100 a.a is called polypeptide

Protein structure

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1) amino acid sequence
2) rod (alphar helix) or flat sheet (b pleated)
3) folding of protein 3D shape
4) combination of individual polypeptide chain eg. hemoglobin

Bonds

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amino acid held together by peptide bonds. Proteins are usually negatively charge Pr-

Cellular organelles

21702772 — 2017-12-10 14:59:02 UTC

How does cell maintain constant environment? Using internal structure of cellular organelles

Monomer vs Polymer

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Glucose- Glycogen
Fatty acid- triglycerides
amino acid- quartenary protein
nucleotides- polynucleotide (R/Dna)
(ATCGU) - ribose sugar- phopshate

Ribosomes

21702772 — 2017-12-10 15:03:50 UTC

protein synthesis - primary structure not 2,3,4 structure. Made up of 2 subunit (large/small -rRNA+protein) rRNA build in nucleolus. Ribosomes are found in cytoplasm, some are free, some attached to endoplasmic reticulum

ATP

21702772 — 2017-12-10 15:08:32 UTC

x3 phophate- ribose sugar- nucleotide. ADP+ PO³_⁴ + E--- ATP + H₂0. Cant store ATP

Mitochondria

21702772 — 2017-12-10 15:11:59 UTC

make ATP as fuel according to usage, not stored. Thyroid control rate of conversion. In cytoplasm Glucose breakdown into 2 pyruvic acid generating 2ATP. (glycolysis, anaerobic). Mitochondria further break up pyvruvate but need oxygen and produce 34 ATP (aerobic). It has unusual double membrane -outer & inner (cristae)

Glycolysis

21702772 — 2017-12-10 15:17:32 UTC

Skeletal muscle depends on glycolysis for ATP production during active contraction period or running out of breath for a brief periods. However mitochondrial activity provides most of ATP required by cells when O2 is available.

Apoptosis

21702772 — 2017-12-10 15:21:08 UTC

activation of suicide gene. Self program to self destruct upon reaching its shelf life. eg. cell is suppose to only live for 5 days, it will self destruct at day 5. It is different to cell death cause by denaturation or bursting(autolysis) of lysosome. Three ways of clearing cells/protein- 1)lysosome 2)proteosome (ubiquitin) 3)apoptosis

Cell life cycle

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changes in morphology, cell self destruct in order to divide. Growth, differentiation, make different, morphology.

Cell response to demand

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hyperplasia and hypertrophy- metaplasia- dysplasia. Tumourogenesis- dysplastic cells compete against each other. Dysplasia often reversible but not the word always reversible.

Epithelia tissue characteristic

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S- specialize contact -attachment to basal lamina
C- cellularity- closely bound by cell junction (occluding, gap, desmosome)
R- Regeneration (continual division of stem cell at basal lamina)
A- Avascular
P- Polarity [different structure and function between top (apical) & bottom (basal)]

Connective tissue framework

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1) Specialized cell
2) Extracellular Protein Fibres
3) Ground Substance
2&3 make up MATRIX

Mast cells

21702772 — 2017-12-10 15:50:39 UTC

are CT near blood vessels.
is filled with Histamine & Heparin.
Histamine released after injury or infection, and stimulates local inflammation. Macrophages will follow the trail or migrate via chemotaxis.

Four type of membranes

21702772 — 2017-12-10 15:54:29 UTC

make up of epithelial tissue supported by connective tissue.
Mucous- digestive, respiratory
Serous- Ventral body cavity
Synovial- Joint
Cutaneous- Skin

Serous membrane

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Lines ventral body cavities
pleura- lines pleura cavities cover lungs
pericardium- lines pericardial cavity cover heart
peritoneum- line peritoneal cavity cover enclosed organs
Parietal and Viscera portion- former lines inner surface of cavities, later cover viscera organs surfaces. Always in close contact and lubricated with fluids

Bone tissue (osseous)

21702772 — 2017-12-10 19:22:47 UTC

Compact bone- form protective layer surrounding medullary cavity which store red and yellow marrow.
Spongy bone (trabecular bone) resemble latticework is covered by a layer of compact bone.
Medullary cavity is part of trabecular bone.

4 type of bone cells

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osteocytes- matured to maintain matrix
osteoblast- secrete bone matrix
osteoclast- bone resorption
osteoprogenitor- stem cells

Osteoctyes

21702772 — 2017-12-10 19:32:49 UTC

osteocyte found in lacuna which is sandwiched between layers of lamellae. Canaliculi penetrate lamellae and contains extension of osteocytes. Osteocytes are linked to each other by gap junctions which allow nutrients exchange. It can dissolve matrix and release mineral, it can rebuild matrix by deposit new hydroxyapatite. It can de differentiate to osteoblast if release from lacunae.

Factors affects bone growth

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hormones- human growth hormone, estrogen, testosterone stimulate osteoblast activity. Bone mass peaks at 30. osteoclast inhibited by oestrogen and high CA². Lifestyle, medical, genetics

Exercise

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important for stronger bones. Moderate amount of physical activity and weight bearing activities are essential for stimulating normal bone maintenance and strength. Without stress, bone become thin and brittle.

Why Exercise

21702772 — 2017-12-10 19:40:50 UTC

when you jump or bear weight or move, Hydroxyapatite crystal (ca, phosphate, water) breaks and release piezoelectric (charges) which attract osteoblast to lay down calcium at site of stress (increase bone density).

Bone remodel

21702772 — 2017-12-10 19:55:00 UTC

remodelling continuously recycles and renews bone matrix. It goes on throughout life. It is essential for calcium homeostasis and maintaining integrity of skeleton. Osteoblast and osteoclast activity are in balance, while osteocyte continuosly remove and replace its surrounding calcium. Old bone are destroyed by osteoclast, while new bone are constructed by osteoblast.

Bone turnover

21702772 — 2017-12-10 20:09:21 UTC

refers to total volume of bone that is both resorb and formed over a period of time , expressed as percent/year. It can be estimated by measuring relevant bone biomarkers (enzyme)

High/Low bone turnover

21702772 — 2017-12-10 20:20:41 UTC

High bone turnover means increased bone loss (high turnover osteoporosis). Low bone turnover means bone breakdown is low same as healthy young adults, however the rate of new bone formation is even lower. Ability to repair micro damage of bone is impaired, risk fracture is increased.

Bone matrix

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2/3 mixture of calcium salt (hydroxyapetie)- hard but brittle
the rest is collagen fibre- strong yet flexible

Transverse tubules

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continuous with sarcolemma and extend into sarcoplasm, forms a passageway through the muscle fiber so nerve impulse could reach. Combination of a pair of terminal cisternae(packed with Ca) plus a t-tubule is called a TRIAD.

Thin filaments

21702772 — 2017-12-10 22:41:00 UTC

F actin- twisted filamentous strand
G actin- globular molecule
Nebulin- hold f actin strand together
Tropomysin- cover active site on G actin
Troponin- bound to tropomycin

Thick Filament

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held together by titin (elastic/recoil)
Head & Tail

Muscle structure

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myofilament-sarcomere-
myofibrils-muscle fiber-endomysium- fasicles- perimysium- epimysium- entire muscle.
sarcolemma- muscle fiber's cell membrane.
epimysium, perimysium, endomysium are connective tissues. Comes together to form tendon.

Recruitment

21702772 — 2017-12-10 22:54:58 UTC

CNS recruit a number of motor units together to increase strength of contraction. This recruitment process is smooth and steady from small to larger motor units

ATP

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ATP+ creatine ---- ADP + creatine phosphate

Endurance

21702772 — 2017-12-10 23:04:04 UTC

Initial burst of run used up energy/ ATP generated from creatine phosphate. This energy can only sustained for 15secs. During this period of time, mitochondria will produce ATP via aerobic respiration whereby glycogen is broken down to glucose. When energy demand is low and O2 abundant, glycolysis provide substrate for aerobic metabolism. However during peak muscular activity, energy demand high and O2 limited. Glycolysis, anaerobic respiration provide most of the ATP to sustain muscle contraction.

Fast vs Slow fiber

21702772 — 2017-12-11 00:05:22 UTC

diameter- large vs small
fatigue resistance- low vs high
speed- fast vs slow
color- white vs red
mitochondria- few vs many
capillary- scarce vs dense
myoglobin- low vs high
glycolytic enzyme- high vs low
substrate for ATP- glucose vs lipids,carbs
anerobic vs aerobic

Lactic acid

21702772 — 2017-12-11 00:10:39 UTC

At peak level exertion, muscle rely on glycolysis for ATP. However when glycolysis produces pyruvic acid faster than it can be used by mitochondria, pyruvic acid level rises in sarcoplasm. They are then converted into lactic acid which can lower the pH. Eventually key enzyme can change shape resulting muscle fiber unable to continue contraction. During recovery period, LA can be converted back to PA

Anerobic Endurance

21702772 — 2017-12-11 00:16:40 UTC

length of time muscular contraction can continue to be supported by glycolysis and the reserve of ATP and CP. To improve AnE involve frequent, brief, intensive workout that stimulate muscle hypertrophy.

Aerobic endurance

21702772 — 2017-12-11 00:17:40 UTC

length of time a muscle can continue to contract while supported by mitochondrial activities. To improve AE involves sustained low level of muscular activity.

Quick Test multiple choice qs

21702772 — 2017-12-11 02:50:19 UTC

just to test my up to date knowledge

Answer to Quick Test

21702772 — 2017-12-11 02:58:30 UTC

Life's unfair i decide which is correct

Function of Bone

21702772 — 2017-12-12 14:21:34 UTC

Some Men Prefer Mini Skirt But Can't Find Enough Skin
Support, Movement, Protection, Mineral Storage, Blood Cell Formation, Energy Reserve

Skeletal system

21702772 — 2017-12-12 14:29:54 UTC

Main components are: Bones of skeleton, cartilage, ligaments and joints. Not included -blood, tendon

Bone formation

21702772 — 2017-12-12 14:38:03 UTC

Endochondral ossification- Interstitial growth & appositional growth, uses hyaline cartilage as model
Intramembranous ossification- osteoblast differentiate within a fibrous connect tissue resulting dermal bones eg. skull, mandible, clavicle

Heterotopic bone formation

21702772 — 2017-12-12 14:44:18 UTC

Dermal bones forming in abnormal locations. Rare genetic disease FOP (fibrodysplasia ossificans progressiva)

Bone Marrow

21702772 — 2017-12-12 14:50:47 UTC

Red BM diminish at lates 20's to early 30's (make RBC & WBC) hence, younger is fitter and older gets injured or run out of gas easier and more likely to get disease.
Yellow BM- adipose tissue for energy reserve replace RBM. When bone fractures & damage vessels, Fat get released into bld vessels, triglyceride insoluble in h20 causes clog. This explain why elderly fall can cause death (hip most prone follow by wrist)

Bone pathology

21702772 — 2017-12-12 15:13:33 UTC

1) Mineralisation problem- Heavy metal ions incorporated into matrix of bone due to biochemical similarity to calcium. Radiation release by their own bone caused cancer.
2) Hormonal problem- Pituitary growth failure- reduced epiphyseal cartilage activity- short bone. Gigantism- overproduction of growth hormone before puberty. Acromegaly- too much growth hormone in adulthood- bones get thicker especially in face

Muscle contraction

21702772 — 2017-12-12 16:38:21 UTC

Strength is equal to no. of motor unit recruited. eg. pick heavy stuff required 100 motor unit, light stuff 5mu. However to hold the items up, motor unit will fire in a overlapping sequence called (team relay) or rotating basis, which result in smooth sustained muscle contraction, get complete tetanus. where stimulus is in rapid succession.

Relay effect- 20% mu activated, once tired another 20% get activated while former relaxes, eventually cycle will get caught up and all motor units are tired without enough resting period. When this happen, firing timing is out of sync. Get incomplete tetanus and muscle shakes and eventually give up.

Why humans are good marathon runners

21702772 — 2017-12-12 17:02:23 UTC

1) ATP storage by creatine phosphate- generate ATP
2)aerobic respiration with mitochondria
3)anerobic respiration with glycolysis
4) at rest, lactic acid convert back to Pyruvate acid which can be used to generate ATP in mitochondria or convert glucose to glycogen
5)Fatty acid can generate ATP as well in mitochondria
As long we have enough fuel (glycogen/fats) in the body we can keep on running as we are constantly generating ATP.

Motor unit

21702772 — 2017-12-12 18:43:58 UTC

is a motor neuron and muscle fibers it controls. Precise movement has small motor unit (less muscle fiber in the motor unit). eg eye movement

compare incomplete tetanus to summation wave

21702772 — 2017-12-12 18:46:42 UTC

IT- muscle produce near peak tension during rapid contraction and relaxation
SW- adding of one twitch to another

Peak tension

21702772 — 2017-12-12 18:48:07 UTC

is affected by frequency of stimulation and muscle fiber type stimulated and recruitment of motor unit.

sliding filament

21702772 — 2017-12-12 18:51:35 UTC

during contraction only I band and H zone become smaller. A band remains the same.

Myasthenia gravis

21702772 — 2017-12-12 19:31:14 UTC

autoimmune neuromuscular disease characterize by muscle weakness. Eye, face, swallow. eg droopy eyelid, double vision, trouble talking, slur speech. Antibodies attack acetylcholine receptor, prevent nerve impulse to trigger muscle contraction.

Muscle Contraction mechanism

21702772 — 2017-12-12 19:36:57 UTC

Action potential travels along the nerve and reaches terminal end of neuron(synapse). AcetylCh vesicle release across synaptic cleft and attach to Ach receptors located at motor end plate which is situated on folding site of sarcolemma. Next, action potential generated at sarcolemma and travels to T-tubules. Calcium is released from SR & terminal cisternae. Ca²⁺ binds to troponin, then tropomycin is rolled over away from active site on actin allowing energised myosin to form cross bridge link. Power stroke is performed and Phosphate molecule together with ADP is released from myosin head. Next, ATP will come along bind to myosin head to breakup the cross bridge and reset myosin head (reenergised-ATP breakdown into ADP+P again). Cycle repeats as long CA²⁺ and ATP are sufficient.

Rigor Mortis

21702772 — 2017-12-12 19:53:22 UTC

Corpse stiffen due to sustained contraction of muscle. Without ATP, cross bridge form between myosin and actin couldnt breakup/detach. So body remains contracted/lock until 72hours whereby autolysis breaks everything down.