Physical laws involving:

strength, diffusion, movement, and heat exchange

Water 1000x denser than air

Gives streamline body contour; no bumps

• Body dimensions increase, thicker skeleton needed for support

• Muscles needed for locomotion represent larger fraction of total body mass

• Mobility becomes limited

Tapered on both ends

Rates _________ to _____________,amount that must be

exchanged ______________ to _______________.

proportional;

membrane surface area;

proportional;

cell volume

# cells in the body

• Body plan enables direct exchange between almost all cells/external environment

• Sac-like/flat shapes

• Compact cell masses

• An increase in # cells, decrease of the ration of outer surface area to total volume

•  Specialized surfaces that are banched/folded inside 

• Enable sufficient exchange with environment

• Protects tissue from abrasion/dehydration

• Allows for streamlined body contours

Complex internal organizations also have ___________;

(i.e ____________.)

Circulatory fluid;

Blood

• External skeleton protects against predators

• Sensory organs provide detail information on surrondings

• Internal digestive organs break down food gradually

• Specialized filtration systems adjust composistion of internal fluid that bathes body cells

1. Cells
2. Tissues
3. Organs
4. Organ system

Mouth

Pharynx

Esophagus

Stomach

Intestines

Liver

Pancreas

Anus

Food processing;

(ingestion, digestion, absorption, elimination)

Heart

Blood vessels

Blood

Lungs

Trachea

Other breathing tubes

Gas exchange;

(uptake of oxygen, disposal of carbon dioxide)

Bone marrow

Lymph nodes

Thymus

Spleen

Lymph vessels

White blood cells

Body defense;

(fighting infections and cancer)

Kidneys

Ureters

Urinary bladder

Urethra

Disposal of metabolic wastes;

regulation of osmotic balance of blood

Pituitary

Thyroid

Pancreas

Adrenal

Other hormone-secreting glands

Coordination of body activites;

(such as digestion and metabolism)

Ovaries

Testes

Associated organs

Brain

Spinal cord

Nerves

Sensory organs

Coordination of body activities;

Detection of stimuli;

Formulation of responses to stimuli;

Skin and derivatives

(hair, claws, skin glands)

• Protection against:

Mechanical injury

Infection

Dehydration

• Thermoregulation

Skeleton

(bones, tendons, ligaments, cartilage)

Body support

Protection of internal organs

Movement

1. Epithelial
2. Connective
3. Muscle
4. Nervous

• Sheets of cells, closely packed with tight junctions

• Covers outside body and lines organs/cavities within body

• Form active interfaces with environment

• Function as barrier against mechanical injury pathogens and fluid loss

• Dice shaped cells specialized for secretion

• Makes up epithelium of kidney tubules and many glands (thyroid & salivary)

• Large, brick shaped cells

• Found where secretion/active absorption is important

• Lines intestines, secretes digestive juices and absorbs nutrients

• Single layer of platelike cells, thin/leaky
• Functions in exchange of material by diffusion
• Lines blood vessels/air sacs of lungs 

(where diffusion of nutrients and gases is crucial)

• Single layer of cells varying in height

• Ciliated cells forms mucous membrane that lines portions of respiratory tract; beating cilia sweep film of mucus along surface

• Multilayered and regenerates rapidly

• New cells formed by division near basal lamina, push outward, and replace cells that are sloughed off

• Found on surfaces subject to abrasion (outer skin, linings of mouth, anus, and vagina)

• Faces lumen or outside of organ and exposed to fluid/air

• Has outside projections that cover surface (small intestine covered with microvilli)

Opposite side of organ than apical;

Doesn't face lumen, inside organ; not exposed to fluid/air;

Attached to basal lamina

• Sparse population of cells scattered through extracellular matrix

• Holds many tissues/organs together and in place

• Matrix consists of web of fibers embedded in liquid, jellylike, or solid foundation

• Matrix is within fibroblasts and macrophages

Secrete fiber proteins;

Connective tissue

Engulf foreign particles and any cell debris by phagocytosis;

Connective tissue

• Most widespread connective tissue in vertebrate body

• Name from loose weave of fibers, which include all 3 types of tissue fibers

• Binds epithelia to underlying tissues and holds organs in place

• Found in skin and throughout body

• Dense with collagenous fibers
• Found in tendons and ligaments

• Makes up skeleton of most vertebrates
• Mineralized connective tissue (Ca, Mg, and P ions)
• Contains osteoblasts and osteons

Bone forming cells

Deposit matrix of collagen

• Makes up hard mammalian bone;

• Consists of repeating units

• Each has conentric layers of mineralized matrix deposited around central canal of blood vessels/nerves

• Liquid extracellular matrix (plasma)

• Has erythrocytes, leukocytes, and platelets

Red blood cells;

Suspended in plasma

-Carry oxygen

White blood cells;

Suspended in plasma

-Function in defense

Cell fragments;

Suspended in plasma

-Aid in blood clotting

• Specialized loose connective tissue

• Stores fat in adipose cells distributed throughtout matrix

• Pads and insulates body; stores fuel as fat molecules

Adipose tissue:

Each cell contains a large _____ droplet that ______ when fat is _________ and ________ when the body uses fat as _______.

Fat;

Swells;

Stored;

Shrinks;

Fuel

• Contains collagenous fibers embedded chondroitin sulfate

• Contains chondrocytes

• Many vertebrate embryos contain cartilage, but is replaced by bone as embryo matures

• Remains in locations like discs that acts as cushions between vertebrae.

Rubbery protein-carb complex;

Cartilage

• Responsible for nearly all types of body movement

• Consists of filaments containing proteins: ACTIN & MYOSIN

1. Skeletal
2. Smooth
3. Cardiac

• Aka striated muscle

• Attached to bones by tendons

• Voluntary movements

• Consist of muscle fibers

• Arrangement of sarcomeres that gives the cells a striped (striated) look

• Bundles of long cells

• Formed by fusion of many cells, resulting in multiple nuclei in each muscle cell/fiber

Increases size;

Number of fibers

• Lack striations

• Found in walls of digestive tract, urinary bladder, arteries, and other internal organs

• Cells spindle-shaped

• Involuntary body activities (churning of stomach and constriction of arteries)

• Forms contractile wall of heart

• Straited like skeletal and similiar contractile properties

• Has fibers that interconnect via intercalated disks, which relay signals from cell to cell and help synchronize heart contraction

• Functions in receipt, processing, and transmission of information

• Contains neurons and glial cells

• Concentration of nervous tissue forms brain, information process center

Nerve cells;

Transmit nerve impulses and support glial cells;

Contains dendrites

Aka Glia;

Help nourish, insulate, and replenish neurons, and sometimes modulate neuron function

Endocrine system;

Nervous system

• Signaling molecules (hormones) released into bloodstream by endocrine cells that reach all locations

• Hormones are slow acting

• Suited to coordinating gradual changes that affect entire body (growth/development, reproduction, metabolic processes, digestion)

• Use same pathway as nervous system

• Communication usually involves more than 1 type of signal

• Neurons transmit signals (nerve impulses) between specific locations in body

• Impulses travel to specific cells on communication lines that consist of axons over changes of voltage

• Conveys information by pathway the signal takes

• Fast, suited for immediate and rapid response

• Other neurons
• Muscle cells
• Endocrine cells
• Exocrine cells