Download File - Classes with Mrs. Sheetz

Chapter 31:
Human Anatomy &
Physiology
Part 2
Immunologic, Endocrine,
and Excretory Systems
Immune System
• A complex system which protects us
from infectious organisms
• Pathogens: organisms that cause
infection
• Immune system fights off pathogens
such as viruses, bacteria, parasites,
and fungi
• Components:
white blood cells, lymph vessels,
lymph nodes, and tonsils, thymus
gland, spleen (page 655)
Barriers:
• Physical: skin, mucous membranes
of mouth, nose, trachea, lungs
-block pathogen from entering
• Chemical: fluids of eyes, mouth,
stomach
-enzymes and acid kills pathogen
Non-Specific Response
• Responds in a generic way
• Inflammatory response occurs
• Histamine: a chemical which initiates
the inflammatory response; causes
blood vessels to dilate, increases
blood flow to area
• Phagocytes (macrophages &
neutrophils): engulf and remove
pathogens
Specific Response; Immune Response
• Carried out by special white blood
called lymphocytes
• Two branches:
1) humoral response – targets
and/or inactivates pathogens
using antibodies
2) cell-mediated response – kill
infected cells using killer T-cells
• Antigen: a foreign protein that
triggers an immune response
• Helper T-cells: present the pathogen’s
antigen to B-cells and cytotoxic T-cells
• B-cells: makes antibodies directed
toward a specific antigen; target the
antigen for removal
• Cytotoxic T-cells: make proteins called
receptors specific to the one antigen;
sticks to antigen and kills it
• Suppresser T-cells: shut the immune
response off when infection is gone
• Memory: the body has the ability to
remember/recognize a pathogen and
prevent future infection
Active & Passive Immunity
• Active: develops as the result of
being infected by/exposed to a
pathogen
(ie. vaccine)
• Passive: develops as the result of
transfer of antibodies from one
individual to another
(ie. breast-feeding a baby)
Autoimmune Response
• An immune response that is
mounted against a person’s own
body.
*see chart page 660
Endocrine System
• Complex system using chemical
messengers called hormones
• A gland synthesizes a hormone, sends
it into the blood stream to reach a
target organ some distance away.
• Two types of hormones:
*amino acid – not soluble in the cell
membrane; attach to receptors on
the cell
*steroid – soluble in the cell
membrane; attach to receptors in
cytoplasm
Regulation:
• Hypothalamus: main control gland of
endocrine system; tells pituitary
gland which hormones to release
• Feedback inhibition: see example
bottom page 661
• See chart page 663
Excretory System:
• 2 kidneys, 2 ureters, one urinary
bladder, one urethra
• The kidneys filter blood to remove
wastes and conserve water, ions, and
nutrients
• Nephron: the functional unit of the
kidney