Rib Cage and Intercostals Google Images Rib Cage and Intercostals By: Anna Jordan

Respiratory System Organ The 24 bones that surround the lungs make up the ribs. They provide protection and stability to the thoracic cavity because they’re attached to the spinal cord. 10 of the ribs meet at the breast bone but the other two ribs are “Floating Ribs” which don’t attach. Interior Intercostals line the more inner part of the rib Exterior Intercostals are closer to the skin They line the ribs to provide movement for breathing and are controlled by chemoreceptors in the spine Other organs in the rib cage are the heart, lungs, and diaphragm

RIB CAGE The rib cage holds/protects all of the organs Made up of strong cartilage and thick bones Ribs are attached to the spinal cord through a hinge which moves them up and down to make room for the lungs during inspiration/expiration When the ribs are expanded: increased volume of chest + low pressure in lungs = air moves into lungs

Intercostals Intercostals are a skeletal muscle because they contract and are not involuntary (tell yourself to hold your breath) Intercostals work with diaphragm and ribs to move Nerves on spinal cord tell muscles to contract/stretch Ribs follow the stretch and move up and out, diaphragm contracts Nerve signal stops and intercostals relax, pushing air out, diaphragm relaxes Chemoreceptors detect low oxygen levels/ high carbon dioxide levels and tell the intercostal to expand and “breathe quicker”

Impediments of the rib cage and intercostals Broken Rib Bones Damaged Nerves in Spine

Broken Ribs If ribs are broken, it will not move properly with intercostal muscles, so thoracic cavity won’t move, and it’s more difficult to breathe If bone pierces lung…you got issues Bone will pierce lung and, like a balloon, air will leak into the chest and oxygen will not diffuse into the blood. Never mind the pain, you’ll be dead soon. Treatment (scientific): Blood clots form by broken bone and osteoblasts come from periosteal* and make new spongy bone. WBC clean up the mess of blood and osteoblasts produce bony callus to turn spongy bone to compact bone *Periosteal is a membrane that covers the bones Osteoblasts are made to build bones GO TO A DOCTOR!!!

SOURCES Biology Alberta 20-30 Nelson Textbook, page 286 Phone call to Dr. Sandra Rogers (my aunt) Feinberg, Brian. The Musculoskeletal System. Chelsea House Publishers, 1993 (pg. 66-68) http://www.webmd.com/lung/lung-injuries http://www.innerbody.com/image_chest1/chest01.html http://www.yorku.ca/earmstro/journey/intercostals.html www.medicalexhibits.com