Levels of Organization

Inorganic Compounds (no carbon)

• water

• salts (electrolytes)

• acids

• bases

organic compounds (contain carbon)

• carbohydrates (energy)

• lipids (fats, hormones)

• proteins (structure, hormones, enzymes, antibodies, etc)

• nucleic acids (DNA)

all chemicals found in the body are classified as either (carbon, no carbon):

inorganic compounds and organic compounds

cells

basic unit of structure and function

tissues

cluster of connected cells with similar fuctions

histology

the study of the microscopic structure of tissues

the four basic types of human tissues

• epithelial

• connective

• muscle

• nervous

epithelial tissue

made up of cells that line the inner outer body surfaces to protect the body and its internal organs, and secrete and absorb substances

Ex. skin, lining of digestive tract

cell shape of epithelial tissue

• squamous (flat)

• cuboidal

• columnar

arrangement of epithelial tissue

• simple (thin, single layer, good for secretion, absorption, filtration)

• stratified (multi layered, durable, protection)

connective tissue

made up of cells that form the body’s structure

Ex. bone, cartilage, adipose (fat)

classification of connective tissue

• dense connective: collagen fibers that form strong, rope-like tissue

• loose connective: softer, more cells, less fibers

  • areolar: hold organs in place + provide protection

  • adipose: fat tissue, insulation/protection

  • reticular: recticular fibers that help support freely moving cells (blood cells)

muscle tissue

made up of cells that have the unique ability to contract, or become shorter. Muscles attached to bones enable the body to move.

nervous tissue

made up of neurons, or nerve cells, that carry electrical messages. Nervous tissue makes up the brain and the nerves that connect the brain to all parts of the body.

organs

structures that consists of two or more types of tissues that work together to do the same job

organ systems

groups of organs that work together to carry out a complex overall function. Each organ of the system does part of the larger job

homeostasis

the condition of equilibrium (balance) in the body’s internal environment due to the constant interaction of the body’s many regulatory processes

5 basic regulatory processes:

1. metabolism

2. movement

3. growth

4. differentiation

5. reproduction

metabolism

the sum of all the chemical processes that occur in the body

catabolism

the breakdown of complex chemical substances into simpler components (example: digestion of proteins in food to amino acids)

anabolism

is the building up of complex chemical substances from simpler components (example: amino acids being used to build new proteins that form muscles and bones)

movement

the motion of the whole body, individual organs, single cells, and even tiny structures inside cells.

Ex. The coordinated movement of your leg muscles to move your whole body when you walk or run.

growth

an increase in body size that results from an increase in the size of existing cells, an increase in the number of cells, or both

differentiation

the development of a cell from an unspecialized state to a specialized state

(stem cells are precursors to cells that give rise to cells that undergo differentiation)

reproduction

to the formation of new cells for tissue growth, repair, or replacement

order of feedback loops

1. stimulus

2. sensor

3. control

4. effector

*continues until sensor no longer detects a stimulus (return to homeostasis)

set point range

normal range the body tries to stay within

stimulus

an imbalance in homeostasis outside the Set Point Range

sensor

monitors the change and sends “input” (examples: nerve impulses, chemical signals) to the control center (brain)

control

processes “input” and releases “output” (different nerve impulses, chemical signals)

effector

receives the “output” and produces the response.

negative feedback loop

• more common than positive

• counteracts change, returning to homestasis

• Ex. body temp, glucose levels

positive feedback loop

• less common than negative

• amplifies changes, moving away from homeostasis

• Ex. fever, childbirth contractions

anatomical position

• Standing upright

• Facing the observer

• Head level, eyes forward

• Feet flat, directed forward

• Arms at side, palms forward

prone

laying face down

supine

lying face up

head

skull and face

neck

supports the head and attaches it to the trunk

trunk

chest, abdomen, and pelvis

upper limbs

shoulders, arms

lower limbs

buttocks, thighs, legs

body cavities

spaces within the body that help protect, separate, and support internal organs

1. Cranial Cavity

2. Vertebral Cavity

3. Thoracic Cavity

4. Abdominal Cavity 

5. Pelvic Cavity

cranial & vertebral cavities

• formed by skull and vertebrae of the spine

• contain the brain and spinal cord

• lined with layer of protective tissue called meninges

thoracic cavity

• Pleural Cavities- contain the lungs

• Pericardial Cavity- contains the heart

• Mediastinum - contains the esophagus, trachea, thymus, and pericardial cavity

• Diaphragm- dome shaped muscle that separates the thoracic and abdominopelvic cavity.

abdominopelvic cavity

• Abdominal Cavity - contains stomach, spleen, liver, gallbladder, small intestine, and most of large intestine

• Peritoneum- thin slippery membrane that lines the abdominal cavity and the organs it contain

• Pelvic Cavity - contains urinary bladder, part of large intestine, and internal reproductive organs

superior vs inferior

above vs below

posterior (dorsal) vs anterior (ventral)

towards back vs towards front

medial vs lateral

towards center vs away from center

proximal vs distal

closer to trunk vs further from trunk

superficial vs deep

close to surface vs further from surface

frontal plane

divides the body into anterior and posterior (front, back)

transverse plane

divides the body into superior and inferior (above, below)

sagittal

divides the body into right and left

midsagittal

divides the body evenly at the midline