human bio 2024

breathing

inhalation and exhalation of gases within the lungs

gas exchange

o2 and co2 exchange across the tissues of the alveoli to and from the blood

transport of gases

travel from the lungs to every cell and back again

cellular respiration

the release of energy within the cells

pleura

membrane covering the surface of the lungs

pleural membrane

allows lungs to slide against the chest wall

bronchi

spilt off into millions of bronchioles which are made of smooth muscle and elastin to control airflow

alveoli

tiny air sacs located at the end of each bronchioles, only one cell thick, moist lining of the alveoli enables gases to dissolve, surrounded by a capillary network and site of o2 and co2 exchange

features of exchange surfaces

large surface area, thin only one cell thick walls, moist exchange surface and constant blood supply

emphysema

alveoli is damages, losing elasticity and lungs remain inflated which reduces surface area for gas exchange and reduced ventilation

emphysema - C, S, T

caused by long term exposure to high amounts of irritating particles in the air, symptoms include forced exhalation, coughing, susceptibility to chest infections and there is no cure

asthma

irritation of the membranes lining the lungs and during an attack it causes the muscles around the bronchioles to spasm, narrowing passages

asthma - C, S, T

an allergic response to foreign substances, symptoms can include wheezing, coughing, tight chest and can be treated with ventolin

cardiac muscle

involuntary, striated, uninucleated and makes up the tissue of the heart and pumps blood around the body

skeletal muscle

voluntary, striated, multinucleated and attached to bones and involves in the movement at joints

smooth muscle

involuntary, unstriated, multinucleated and involved in movement like peristalsis in the intestines

muscle characteristics

contractability, extensibility and elasticity

structure of skeletal muscle

skeletal muscle, bundles of muscle fibers, myofibrils, myofilaments and actin & myosin

connective tissues

muscle cells are held together in bundles surrounded by CT, which allows the bundles to slide over each other during contraction, CT around each muscle join at the end of the muscle to form a tendon which attaches muscles to bones

muscle cells

elongated cylinders with many nuclei which lie parallel to each other, the cylinders are called muscle fibers which can be from 1-2mm to 7cm

muscle fibres

each muscle fibers contain myofibrils which are surrounded by a plasma membrane called the sarcolemma which contains a cytoplasm called sarcoplasm

sarcoplasmic reticulum

specialised type of smooth ER that regulates calcium ions in muscle cells

myofibrils

divides into units called sarcomere and is composed of myofilaments which are proteins, thick myofilaments are myosin and thin myofilaments are actin which slide past each other during muscle contraction

sliding filament theory

muscle relaxed: sarcomere lengths and muscle contracts: sarcomere shortens but the actin and myosin never change in length

belly

fleshy part of the muscle between the origin and insertion points

origin and insertion

origin: where the muscle is fixed to a stationary bone and insertion: where the muscle is fixed to a moveable bone

antagonistic pairs

pairs of muscles working together to move bones in opposite directions

agonist and antagonist

agonist: muscle contracting causing the desired action and antagonist: muscle relaxing allowing the agonist to move the limb

synergist and fixator

synergist: muscles that help agonist by producing the same movement or steadying the action and fixator: muscles which prevent unwanted movement

functions of the skeleton

protection, shape, support, movement, blood production and storage

axial and appendicular skeleton

axial: support for main posture and protects organs and central nervous system and appendicular: bones of the upper and lower limbs

types of bones

flat, short, long ,irregular and sesamoid

fibrous joint

no movement, hard to damage and bones held together by fibrous connective tissues eg. skull

cartilaginous joint

held in place by cartilage which allows slight movement eg. vertebrae

synovial joint

movement limited by ligaments, muscles, tendons and adjoining bones

types of synovial joints

pivot, condyloid, ball & socket, gliding, saddle and hinge

osteoporosis

loss of bone mass with age causing them to become weak and fragile

osteoporosis - C, S, T

caused by age, gender, history, no initial symptoms but later stages include back pain, loss of height and treatments include medications and hormone therapy

osteoarthritis

breakdown of cartilage inside a joint

osteoarthritis - C, S, T

caused by being overweight, previous injury, history, symptoms include stiffness, joint instability, reduced ROM and treatments can include exercise, surgery and pain relief

cartilage

connective tissue, fibers of proteins called collagen are embedded in a firm protein-carbohydrate complex called chondrin which provides support and flexibility

chondroblasts

cartilage cells which produce a matrix around themselves

chondrocytes

mature chondroblast cells which are surrounded by the lacunae

lacunae - cartilage

small spaces between the chondroblasts and matrix

perochondrium

fibrous membrane of connective tissue that contains blood vessels covering the external surface of cartilage

3 types of cartilage

hyaline, elastic and fibrocartilage

hyaline cartilage

closely packed collagen fibers, very thin, provide strength and flexibility and found in the trachea and bronchi

elastic cartilage

elastic fibers, loosely packed collagen fibers, slight thicker fibers, provide flexibility and elasticity and found in the external ear

fibrocartilage

parallel bundles of thick collagen fibers, toughest cartilage, can be compressed to withstand pressure and found in the intervertebral discs of the spinal cord

ossification

the process of bone formation

diaphysis

bone shaft which is made up of compact bone surround a cavity

yellow bone marrow

cavity used to store fats

epiphysis

enlarged ends of the bone covered in articular cartilage which is compact bone on the outside but spongy bone on the inside which is porous and filled with bone marrow

periosteum

dense outer surface of the bone which isnt at joints

bone matrix

bone is a connective tissue which consists of cells separated by a non-cellular material called the matrix, which contains inorganic salts which increases the strength and rigidity

osteons

compact bones

central canal

channel done the center of an osteon containing at least one blood capillary and may contain nerves which runs parallel to the bone, maximising the strength

lamellae

concentric layers of a bony matrix surrounding the osteon which is where calcium is stored

lacunae - bone

small spaces in the matrix

osteocyte

a bone cell occupying each lacuna

canaliculi

tiny canals between lacunae which allows bones to make contact through tiny projections and transportation of nutrients between cells and osteocytes

trabeculae

spongy bone consisting of thin bony plates and an osteocyte occupies the space in the trabeculae, but the lamella is not arranged in concentric layers with nerves and blood vessels passing through spaces in the matrix

functions of the urinary system

excretion and removal of metabolic waste, elimination of foreign substances, water regulation and controls the concentration of the compounds in the extracellular fluid (pH)

urea

the main waste in the human body, it is produced when food containing protein is broken down and it is filtered from the blood and then expelled in the urine

amount of urine production

amount of fluid and food consumed, fluid loss through sweat and breathing and certain types of medications

filtration

occurs from the glomerulus into the bowmans capsule, high blood pressure forcing protein-free plasma out of the blood including water, urea and hormones

reabsorption

occurs along the length of the nephron, selective movement of filtered substances back into the capillaries by diffusion and active transport and results in water diffusing back by osmosis

ADH

anti-diuretic hormone which helps reduce the water loss in urine

secretion

occurs in the distal convoluted tubule with ions like hydrogen, ammonium and potassium being secreted from the blood to help maintain the bodys pH levels

excretion

removal of waste from the metabolism which are different chemical reactions that take place within cells

excretion organs

lungs, skin, liver and kidneys

excretion from skin

helps regulate body temperature, secrete around 500ml of water daily and it consists of urea, sodium chloride, water and lactic acid

deamination

removal of the amino group from the amino acid in the liver by enzymes, the amino group gets converted into ammonia then urea and secreted in the urine and the amino acid gets converted to a carbohydrate which can be broken down to release energy

deamination equation

amino acid + oxygen - enzyme - carbohydrate + ammonia

ammonia to urea equation

ammonia + energy + carbon dioxide - urea + water

excretion from liver

process and breakdown excess proteins which cant be stored they can be broken down into amino acids which can be reused etc.

functions of blood

transport o2, co2, nutrients and waste, defence against diseases, thermoregulation, blood clotting and maintaining pH of body fluids, water content and ion concentration

red blood cells - erythrocytes

no nucleus, last 120 days, made in bone marrow, broken down by liver, biconcave disc and contains haemoglobin

white blood cells - leucocytes

remove dead or injured cells, remove invading organisms and live from a few minutes to a few years

platelets - thrombocytes

small cell fragments, formed in bone marrow, live for 7 days, responsible for blood clotting and 1/3 size of red blood cells

transport of oxygen

97% of oxygen is carried in haemoglobin and 3% dissolve in plasma, o2 and hb combine when o2 concentration is high and hbo2 breaks down when o2 concentration is low

transport of oxygen equation

haemoglobin + oxygen - oxyhaemoglobin

transport of carbon dioxide equation

carbon dioxide + water - carbonic acid - bicarbonate ions

transport of nutrients and waste

inorganic nutrients including calcium, chloride and potassium ions, organic nutrients including glucose, amino acids and glycerol and wastes including urea, uric acid and creatine

plug

injury: walls of the artery affected constrict, platelets stick to site of injury and release chemicals to maintain vasoconstriction

blood clots - coagulation

injury: chemical produce threads of protein called fibrin which a fibrin mesh traps red blood cells, platelets and plasma resulting in clotting and then the fibrin retracts, squeezing of serum causing the clot to dry and scab

universal donors

people with type o blood type are called universal donors

universal recipients

people with type ab blood type are called universal recipients

rh positive

rh+ antigen is present in the blood which means the person cant produce an anti-rh antibody that reacts with those antigens

rh negative

rh- antigen is not present in the blood which means the person can produce an anti-rh antibody that reacts with those antigens

blood transfusion

blood is given to a patient through an IV line in one of the blood vessels which is done to replace blood lost during surgery, serious injury or if a persons body cant make blood properly due to illness

mixing of blood types

mixing blood types that are incompatible can cause the erythrocytes to clump together or agglutinate and if the receivers blood contains antibodies which work against the antigen on the donors red blood cells the foreign cells will clump together and disintegrate

heart

made up of cardiac muscle, contains lots of mitochondria, double pump and surrounded by a pericardium membrane

mammalian circulatory system

made up of the pulmonary circulation and systemic circulation

pulmonary circulation

consists of all the vessels involved in transporting blood between the heart and the lungs

systemic circulation

consists of all the vessels involved in transporting blood between the heart and the body excluding the lungs

atrioventricular valves

valves between the atria and ventricles which are flaps of tissues held by tendons called chordae tendineae and attached to the heart on papillary muscle

semilunar valves

valves between the ventricles and arteries which stop blood from flowing back to the ventricles

the cardiac cycles

atrial systole: blood pumped into ventricles from atria, ventricular systole: blood pumped into the aorta and pulmonary artery and diastole: the atria and ventricles relax, filling with blood

arteries

thick muscular walls, carry oxygenated blood away from heart, small lumen, walls can relax and constrict and arterioles which is the branching of arteries into the capillaries