Human Anatomy Body System Structure & More

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Cellular level

Cellular level - cells & molecules are made up of the basic chemical components (a single phospholipid molecule)

The Human Body Plan

Humans are vertebrates, all vertebrates share six different features 1) Tube-within-a-tube body plan 2) Bilateral symmetry 3) Dorsal hollow nerve cord 4) Notochord and vertebrae 5) Segmentation 6) Pharyngeal pouches

Pharyngeal pouches

Humans have a pharynx, which is the throat region of the digestive and respiratory tube. IN the embryonic stage, the human pharynx has a set of outpocketings called pharyngeal pouches that correspond to the clefts between the gills of fish. Such pouches give rise to some structures in the head and neck

Organ level

Organ level - organs are made up of several tissue types (blood vessels, liver, brain, femur)

Organ system level

Organ system level - an organ system is a unified group of organs and tissues that perform a specific function (cardiovascular system - blood vessels, blood, & the heart)

Organismal level

Organismal level - the whole person is the most complex level of organization (all simpler levels working independently but as one)

Tissue level

Tissue level - tissues consist of similar types of cells and associated extracellular material (epithelial tissue)

Dorsal hollow nerve cord

all vertebrate embryos have a hollow nerve cord running along their back in the median plane which develops into the brain and spinal cord

Muscular system

allows manipulation of the environment, locomotion, and facial expression, maintains posture and produces heat (skeletal muscles

Chemical level

atoms are tiny building blocks of matter (carbon, hydrogen, etc...)

Cardiovascular system

blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc; the heart pumps blood (heart & blood vessels)

Digestive system

breaks down food into absorbable units that enter the blood for distribution to body cells, indigestible foodstuffs are eliminated as feces (oral cavity, esophagus, liver, stomach, small intestine, large intestine, rectum & anus)

Urinary system

eliminates nitrogenous wastes from the body, regulates water, electrolyte, and acid-base balances of the blood (kidney, ureter, urinary bladder & urethra)

Integumentary system

forms the external body covering and protects deeper tissues from injury, synthesizes vitamin D and houses cutaneous receptors (pain, pressure, etc.) [hair, skin & finger/toenails]

Endocrine system

glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells (pineal gland, pituitary gland, thyroid gland, thymus, adrenal gland, pancreas, testis & the ovary)

Respiratory system

keeps blood constantly supplied with oxygen and removes carbon dioxide, the gaseous exchanges occur through the walls of the air sacs of the lungs (nasal cavity, pharynx, larynx, trachea, bronchus & lungs)

Male and Female Reproductive systems

overall function is production of offspring, testes produce sperm and male sex hormone, and male ducts and glands aid in delivery of sperm to the female reproductive tract. Ovaries produce eggs and female sex hormones while the remaining female structures serve as sites for fertilization and development of the fetus, mammary glands of female breasts produce milk to nourish the newborn.

Lymphatic system/Immunity

picks up fluid leaked from blood vessels and returns it to blood, disposes of debris in the lymphatic stream, houses white blood cells (lymphocytes) involved in immunity, the immune response mounts the attack against foreign substances within the body (red bone marrow, thymus, lymphatic vessels, thoracic duct, spleen & lymph nodes)

Skeletal system

protects and supports body organs and provides a framework the muscles use to cause movement, blood cells are formed within bones, bones store minerals (bones and joints)

Segmentation

the "outer tube" of the body shows evidence of segmentation. Segments are repeating units of similar structure that run from the head along the full length of the trunk. IN humans, the ribs and the muscles between the ribs are evidence of segmentation, as are the many nerves branching off the spinal cord. The bony vertebral column, with its repeating vertebrae, is also segmented.

The Hierarchy of Structural Organization

the chemical level, cellular level, tissue level, organ level, organ system level and organismal levels are the 6 levels that, from smallest to largest, make up the basic building blocks of the human body.

Nervous system

the fast-acting control system of the body, responds to internal and external changes by activating appropriate muscles & glands (brain, nerves & spinal cord)

Tube-within-a-tube body plan

the inner tube extends from the mouth to the anus and includes the respiratory and digestive organs the outer tube consists of the axial skeleton and associated axial muscles that make up the outer body wall, and nervous structures

Bilateral symmetry

the left half of the body is essentially a mirror image of the right half, most body structures occur in pairs, but structures in the median plane are unpaired but tend to have identical right and left sides (the nose for example)

Notochord and vertebrae

the notochord ("back string") is a stiffening rod in the back just deep to the spinal cord. In humans, a complete notochord forms in the embryo is quickly replaced by the vertebrae, bony pieces of the vertebral column or backbone. Some of the notochord persists throughout life as the cores of the discs between the vertebrae