Human Body Organs & Functions (CSV)

	A	B	C	D	E	F
H	System	Organ / Structure	Location in Body	Average Weight (g)	Primary Function	Key Facts
2	Cardiovascular	Heart	Chest (mediastinum)	300	Pumps blood throughout body	Beats ~100000 times/day; ~5L blood pumped per minute at rest
3	Cardiovascular	Aorta	Chest & abdomen	N/A	Largest artery; carries oxygenated blood from heart	~30 cm long; 2.5–3.5 cm diameter
4	Cardiovascular	Vena Cava	Chest & abdomen	N/A	Largest veins; return deoxygenated blood to heart	Superior and inferior vena cava
5	Respiratory	Lungs	Chest (thoracic cavity)	500 each	Gas exchange (O2 in / CO2 out)	Right has 3 lobes; left has 2 lobes; total surface area ~70 m²
6	Respiratory	Diaphragm	Below lungs	N/A	Main muscle of breathing; separates thorax from abdomen	Contracts during inhalation
7	Respiratory	Trachea	Neck & upper chest	N/A	Airways passage from larynx to lungs	~12 cm long; reinforced by C-shaped cartilage rings
8	Digestive	Liver	Upper right abdomen	1500	Detoxification / bile production / protein synthesis / glycogen storage	Largest internal organ; only organ that can fully regenerate
9	Digestive	Small Intestine	Abdomen	~1000	Nutrient absorption	~6–7 m long; lined with villi for absorption
10	Digestive	Large Intestine	Abdomen (peripheral)	~400	Water absorption / waste formation	~1.5 m long; houses most gut microbiome
11	Digestive	Stomach	Upper left abdomen	~150 (empty)	Digestion of food; acid production	Holds ~1–1.5L food; secretes HCl and pepsin
12	Digestive	Pancreas	Behind stomach	~80	Produces insulin / glucagon / digestive enzymes	Both endocrine and exocrine gland
13	Digestive	Gallbladder	Under liver	~60 (full)	Stores and concentrates bile	Bile helps digest fats; can form gallstones
14	Digestive	Oesophagus	Neck & chest	N/A	Transports food from mouth to stomach	~25 cm long; uses peristalsis
15	Urinary	Kidneys	Posterior abdomen (pair)	~150 each	Filters blood; produces urine; regulates electrolytes	Filter ~180L blood per day; 1 million nephrons each
16	Urinary	Bladder	Pelvis	~45 (empty)	Stores urine	Holds ~300–500 mL; signals urge at ~150 mL
17	Urinary	Ureters	Abdomen to pelvis	N/A	Carries urine from kidneys to bladder	~25–30 cm long each
18	Endocrine	Thyroid	Front of neck	~25	Regulates metabolism / growth / energy	Produces T3 and T4; requires iodine
19	Endocrine	Adrenal Glands	Above kidneys (pair)	~4 each	Produces adrenaline / cortisol / aldosterone	Two parts: cortex (steroid hormones) and medulla (adrenaline)
20	Endocrine	Pituitary Gland	Base of brain	~0.5	Master gland; controls other hormones	Size of a pea; produces GH / TSH / FSH / LH etc.
21	Endocrine	Hypothalamus	Brain	~4	Links nervous system to endocrine system; temperature regulation	Controls pituitary; involved in hunger / thirst / sleep
22	Endocrine	Pineal Gland	Brain	~0.1	Produces melatonin; regulates sleep-wake cycle	Size of a grain of rice
23	Reproductive (Male)	Testes	Scrotum (pair)	~20 each	Produce sperm and testosterone	External for lower temperature needed for sperm
24	Reproductive (Female)	Ovaries	Pelvis (pair)	~15 each	Produce eggs / oestrogen / progesterone	Contain ~1–2 million follicles at birth
25	Reproductive (Female)	Uterus	Pelvis	~70 (non-pregnant)	Houses and nourishes developing foetus	Expands to ~1100g during pregnancy
26	Nervous	Brain	Skull	~1400	Control centre for body; cognition / emotion / motor control	~86 billion neurons; 2% of body weight; uses 20% of energy
27	Nervous	Spinal Cord	Vertebral column	~35	Transmits signals between brain and body; reflex arcs	~45 cm long; 31 pairs of spinal nerves
28	Nervous	Cerebellum	Back of skull	~150	Coordinates movement / balance / fine motor skills	Contains ~50% of all neurons in the brain
29	Sensory	Eyes	Skull (pair)	~7.5 each	Vision; detects light and converts to neural signals	Can distinguish ~10 million colours
30	Sensory	Ears	Skull (pair)	N/A	Hearing and balance	Cochlea converts sound waves to electrical signals
31	Sensory	Nose / Olfactory	Face	N/A	Smell; also filters and warms air	~400 types of olfactory receptors
32	Sensory	Tongue	Mouth	~80	Taste / speech / swallowing	~10000 taste buds; replaced every 10–14 days
33	Immune / Lymphatic	Spleen	Upper left abdomen	~170	Filters blood / destroys old RBCs / immune response	Can be removed; other organs take over function
34	Immune / Lymphatic	Thymus	Upper chest	~30 (child) / atrophies with age	Matures T-lymphocytes (T-cells)	Most active in childhood; shrinks after puberty
35	Immune / Lymphatic	Lymph Nodes	Throughout body	varies	Filter lymph fluid; house immune cells	~600–700 nodes in human body
36	Musculoskeletal	Skin	Body surface	~3500–5000	Barrier / temperature regulation / sensation / vitamin D synthesis	Largest organ by area (~2 m²); shed completely every ~2–4 weeks
37	Musculoskeletal	Skeletal Muscle	Throughout body	~30000 total	Movement / posture / heat generation	~640 muscles in the human body; ~40% of body weight
38	Musculoskeletal	Bone (skeleton)	Throughout body	~10000 total (206 bones)	Support / protection / blood cell production / mineral storage	Strongest bone: femur; smallest: stapes in ear
39	Musculoskeletal	Bone Marrow	Inside bones	~2600	Produces red and white blood cells	Yellow marrow stores fat; red marrow produces blood cells
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