Transcript The Human Body – An Orientation

The Human Body – An Orientation
• Anatomy – study of the structure and
shape of the body and its parts
• Physiology – study of how the body and
its parts work or function
• Metabolism – all chemical reactions within
the body
• Homeostasis - maintenance of a stable
internal environment
Levels of Structural Organization
Figure 1.1
Biochemistry: Essentials for Life
• Organic compounds
– Contain carbon – except CO2, CO, CO3, HCO3
– Most are covalently bonded
– Examples: glucose, proteins, fats, DNA
• Inorganic compounds
– Lack carbon
– Tend to be simpler compounds
– Example: H2O (water)
Important Organic Compounds
• Carbohydrates
– Contain carbon, hydrogen, and oxygen in the ratio
CH2O
– Include sugars and starches
– Classified according to size
• Monosaccharides – simple sugars. Important fuel
source for body cells. Building blocks of Carbohydrates.
(Ex. Glucose, Fructose, Galactose)
• Disaccharides – two simple sugars joined by
dehydration synthesis. (Ex. Sucrose, Maltose,
Lactose)
• Polysaccharides – long branching chains of linked
simple sugars. (Ex. Starch, Glycogen)
Lipids
Contain carbon, hydrogen, and oxygen
Carbon and hydrogen outnumber oxygen
Insoluble in water
Common lipids in the human body
Neutral fats (triglycerides)
Found in fat deposits (body insulation)
Composed of fatty acids and glycerol
Source of stored energy
Phospholipids
Form cell membranes
Steroids
Include cholesterol, bile salts, vitamin D, and some
hormones
• Proteins
– Made of amino acids.
• Contain carbon, oxygen, hydrogen, nitrogen, and
sometimes sulfur
• 20 different amino acids, 8 of which are essential.
• Account for over half of the body’s organic
matter. Main component of cellular cytoplasm.
– STRUCTURAL PROTEINS - Provides for
construction materials for body tissues (Collagen,
Keratin)
– FUNCTIONAL PROTEINS - Plays a vital role in cell
function (Enzymes, Hemoglobin, Hormones)
Enzymes
• Act as biological catalysts
• Increase the rate of chemical reactions
Figure 2.17
• Nucleic Acids
– Provide blueprint of life
– Nucleotide bases
• A = Adenine
• G = Guanine
• C = Cytosine
• T = Thymine
• U = Uracil
– Make DNA (the stuff of genes) and RNA
Orientation and Directional Terms
Table 1.1
Orientation and Directional Terms
Table 1.1 (cont)
Body Landmarks
• Anterior
Figure 1.5a
Body Landmarks
• Posterior
Figure 1.5b
Cellular Physiology:
Membrane Transport
• Membrane Transport – movement of
substance into and out of the cell
• Transport is by two basic methods
– Passive transport
• No cellular energy is required (simple diffusion,
osmosis)
– Active transport
• The cell must provide metabolic energy
(endocytosis, exocytosis, solute pumping)
Selective Permeability
• The plasma membrane allows some
materials to pass while excluding others
• This permeability includes movement into
and out of the cell
Passive Transport Processes
• Diffusion
– Particles tend to distribute themselves evenly within a
solution
– Movement is
from high
concentration
to low
concentration,
or down a
concentration
gradient
Figure 3.9
Passive Transport Processes
• Types of diffusion
– Simple diffusion
• Unassisted process
• Solutes are lipid-soluble materials or small
enough to pass through membrane pores
Passive Transport Processes
• Types of diffusion
– Osmosis – simple diffusion of water
• Highly polar water easily crosses the plasma
membrane
– Facilitated diffusion
• Substances require a protein carrier for passive
transport
Diffusion through the Plasma
Membrane
Figure 3.10
Passive Transport Processes
• Filtration
– Water and solutes are forced through a
membrane by fluid, or hydrostatic pressure
– A pressure gradient must exist
• Solute-containing fluid is pushed from a high
pressure area to a lower pressure area
Active Transport Processes
• Transport substances that are unable to pass by
diffusion
– They may be too large
– They may not be able to dissolve in the fat core of the
membrane
– They may have to move against a concentration
gradient
• Two common forms of active transport
– Solute pumping
– Bulk transport
Active Transport Processes
• Solute pumping
– Amino acids, some sugars and ions are
transported by solute pumps
– ATP energizes protein carriers, and in most
cases, moves substances against
concentration gradients
– Transports amino acids, sugars, and Na
through the plasma membrane
A
C
T
Active Transport Processes
• Bulk transport
– Exocytosis
•
•
•
•
•
Moves materials out of the cell
Material is carried in a membranous vesicle
Vesicle migrates to plasma membrane
Vesicle combines with plasma membrane
Material is emptied to the outside
Exocytosis
Figure 3.12a
Active Transport Processes
• Bulk transport
– Endocytosis
• Extracellular substances are engulfed by being
enclosed in a membranous vescicle
– Types of endocytosis
• Phagocytosis – cell eating
• Pinocytosis – cell drinking