human physiology 6.1-6.5

ingestion

the taking in of nutrients/food

digestion

the breakdown of complex organic molecules into smaller components by mechanical and chemical means

absorption

the taking up of digested molecules into the cells of the digestive tract through the cell membrane.

egestion

the removal of undigested waste food materials and some metabolic wastes from the body

alimentary canal

the passage through which food passes from mouth to anus

accessory organs

organs that secrete chemicals into the digestive system:
salivary glands, liver, gallbladder, and pancreas

mechanical digestion

physical breakdown of food into smaller particles through processes such as chewing, grinding, and churning

bolus

a small rounded mass of (chewed) food, at the moment of swallowing

peristalsis

a wave of contraction and relaxation of the longitudinal and circular muscles of the alimentary canal, by which the contents are forced along the tube.

oesophagus

A muscular tube that connects the mouth to the stomach in which consumed food and liquid travel down

stomach

large muscular sac that continues the mechanical and chemical digestion of food, by releasing enzymes

small intestine

long, coiled digestive organ where most chemical digestion and absorption of nutrients from digested food takes place

large intestine

The last section of the digestive system, where water is absorbed from food and the remaining material is eliminated from the body

liver

a large organ, involved in processing nutrients, producing bile, and regulating blood sugar.

gall bladder

An organ located beneath the liver that stores bile from the liver and releases it as needed into the small intestine

duodenum

first part of the small intestine

ileum

the last and longest portion of the small intestine

pancreas

located near the stomach, 2 roles exocrine role: to produce digestive enzymes and bicarbonate, delivered to the small intestineendocrine role: to secrete insulin and glucagon into the bloodstream, regulate blood glucose levels.

serosa

outermost layer of small intestine, consists of a thin connective tissue that is in contact with body cavities

longitudinal muscles

responsible for contractions that move contents through digestive tract responsible for peristalsisalong walls of intestine

circular muscles

responsible for peristalsis arranged along walls of small intestine

submucosa

layer of connective tissue directly under the mucosa of SI contains arge veins and arteries which give rise to the capillary bed of the mucosa

mucosa

The innermost layer of small intestine comprised of epithelium, connective tissue, smooth muscle (villi)

nucleases

enzyme, breaks down nucleic acids

maltose

enzyme, breaks down maltose into glucose.

lactase

enzyme that breaks down lactose into galactose and glucose

exopeptidases

enzymes that catalyze the hydrolysis of peptide bonds at the ends of protein or peptide molecules, releasing individual amino acids or smaller peptides

dipeptidases

enzymes that break down dipeptides into individual amino acids, during protein digestion.

goblet cell

a specialized epithelial cell that secretes mucus to protect and lubricate the lining of various organs, notably the respiratory and digestive tracts.

epithelium

tissue that lines the surfaces of organs and body cavities - involved in protection, absorption, and secretion

villi

finger-like projections found in the lining of the small intestine that increase the surface area for nutrient absorption. extensions of mucosa

microvilli

tiny, hair-like extensions on the villi of the small intestine, further increase the absorptive surface area and enhance nutrient absorption

lymph

colourless fluid that carries white blood cells, nutrients and waste products

dextrins

very small polymers still containing the α-1,6 glycosidic bond

dialysis

the separation of smaller molecules from larger molecules in solution by selective diffusion through a partially permeable membrane

arteries

blood vessels that carry blood away from your heart. bring oxygenated blood to the body's cells

capillaries

blood vessels that connect arteries and veins transport blood/nutrients/oxygen to cellsare the smallest blood vessels

veins

blood vessels that carry blood back to your heart

arteriole

small blood vessels that branches off from an artery, connects to capillaries.

capillary bed

interwoven network of capillaries.
When blood leaves an arteriole, it enters a capillary bed rather than a single capillary

vasoconstriction

narrowing of blood vessels. occurs when arteries contract, releasing blood to arterioles

vasodilation

widening of blood vessels, increasing blood flow into arteries

lumen

inside space within a tubular structure

plasma

the fluid in which blood cells are suspended liquid part of blood

atrioventricular valve

valves that separate the atria from ventricles, preventing backflow during systole

semi lunar valves

Valves on either side of the heart that controls exit from the ventricles. located at connections between: pulmonary artery and R ventricleaorta and L ventricle
prevent backflow from arteries into ventricles

sinoatrial node (SA node)

pacemaker of the heart determines heart rategenerates electrical signal that causes atria to contract

atrioventricular node (AVN)

located between ventricles and atria, cluster of cells that receives signal from SA node, passing it to the ventricles, causing them to pump delays signal to ventricles

medulla

in brain - monitors blood pressure and carbon dioxide concentrations using receptors in the arteries.

diastole

relaxation/ventricular filling

systole

ventricular contraction phase of heartbeat, heart pumps blood from chambers into arteries

leptin

a satiety hormone made in adipose tissue.
Helps regulate energy balance by acting on hypothalamus, inhibiting hunger

nervous system

brain, spinal cord, nerveshas cells that transmit electrical signals to control and coordinate various bodily functions.

parasympathetic nervous system

a set of nerves that helps the body return to a normal resting state speeds up digestion to normal rate

erythrocytes

red blood cells - carry oxygen

hepatic artery

carries oxygen-rich blood from the heart to the liver, branch of the aorta

endothelium

a type of epithelium composed of a single layer of smooth, thin cells that lines the heart, blood vessels, lymphatics, and serous cavities.

cardiac muscle

type of striated muscle found in the wall of the heart

atria

atriums of the heart that receive blood from the body and lungs, pass it to ventricles

ventricles

receive blood from atria, then pass blood to the body

right ventricle

pumps blood to pulmonary circulation/the lungs

left ventricle

pumps blood to systemic circulation/body - passes blood to aorta

aorta

largest ventricle, receives blood from left ventricle, carries oxygenated blood to the body

pulmonary veins

brings in oxygenated blood from the lungs to the left atrium

pulmonary artery

receives deoxygenated blood from the right ventricle/pulmonary vein, carries it to the blood to be oxygenated

left atrioventricular valve/bicuspid valve/mitral valve

regulates flow of oxygenated blood from left atrium into left ventricle prevents backflow receives blood from left atrium

right atrioventricular valve/tricuspid valve

regulates flow of blood from the right atrium to the right ventricle

left semilunar valve/aortic valve

regulates blood flow from the left ventricle to the aorta prevents backflow

right semilunar valve/pulmonary valve

regulates blood flow from the right ventricle to the pulmonary artery prevents backflow

inferior vena cava

large vein that carries deoxygenated blood from the lower body to the right atrium

superior vena cava

large vein that brings deoxygenated blood from the upper body to the left atrium

refractory period

Time for cardiac muscle cell membrane to be ready for a second stimulus.

semi-lunar valve

heart valve that prevents the backflow of blood from the major arteries (such as the aorta and pulmonary artery) into the ventricles of the heart

atrial systole

Contraction of the atria of the heart, pushing blood into the ventricles.

ventricular systole

Contraction of the ventricles, forcing blood into the pulmonary artery and aorta.

ventricular diastole

Relaxation of the ventricles, allowing them to fill with blood from the atria.

bundle of His

special bundle of cardiomyocytes, transmits electrical signals from the AV node to the heart ventricles

cardiomyocytes

also called cardiac muscle cells - specialised heart muscle cells, responsible for contractile function

purkinje fibres

located on walls of the ventricles, they carry the electrical signal from the bundle of his - rapidly distribute the signal to large number of ventricular muscle cells

windpipe

trachea

bronchus

one of the two tubes that connect the lungs with the trachea

alveoli

tiny air sacs in the lung, assist in gas exchange between air and blood

Type I pneumocytes

type of alveolus cells
- extremely thin, adapted to carry out gas exchange
- very flat and thin, increasing SA for diffusion

Type II pneumocytes

type of alveolus cells
- secrete a solution containing surfactant
- surfacants create moist lining of alveoli (helps to prevent sticking, moisture helps gases dissolve)

diaphragm

Large, flat muscle at the bottom of the chest cavity that helps with breathing

larynx

voice box; passageway for air moving from throat/pharynx to trachea; contains vocal cords

inspiration

breathing in (inhalation)

expiration

breathing out (exhalation)

antagonistic muscles

muscle pairs arranged to work against each other to move a joint

internal intercostal muscles

muscles located in ribcage - active in expiration
inspiration: relaxes back to elongated state
expiration: muscles that contract, pulling ribcage inwards and downwards

diaphragm during inhalation and exhalation

inhalation: moves down, flattens
exhalation: moves up, becomes domed

ribcage during inhalation and exhalation

inhalation: moves up and outwards
exhalation: moves down and inwards

volume change during inhalation and exhalation

inhalation: increases
exhalation: decreases

external intercostal muscles

muscles in ribcage - active in inspiration
inspiration: muscles that contract, pulling ribcage upwards and outwards
expiration: relaxes back to elongated state

cardiac notch

a concave space on the left lung in which the heart lies
- left lung has two lobes while the right has three to make space for heart

tumour

abnormal groups of cells that develop at any stage of life in any part of the body

benign tumours

groups of abnormal cells that adhere to each other and do not invade other tissues or parts of the body

malignant tumours

Tumours which spread throughout the body and invade other tissue

metastasis

development of a second malignant growth away from site of original growth

carcinogens example

cancer-causing agents
- tobacco
- asbestos