A&P, Skeletal 7_6 .pdf

Block 1 Biology Sci Oly Introduction + Lesson  Overview 01 02 03 Sci Oly Debrief Our 3 Events Expectations 04 05 Lesson! Practice  01 Science Olympiad  What...

Block 1 Biology Sci Oly Introduction + Lesson  Overview 01 02 03 Sci Oly Debrief Our 3 Events Expectations 04 05 Lesson! Practice  01 Science Olympiad  What can I expect for Bio? 1-3 competitions a month, virtual + in-person Intense studying Strong emphasis on cheat sheets Strong community!  Our Events 1 2 3 Anatomy & Microbe Mission Disease Physiology LOTS of Microbiology Detectives Microscopy Disease Skeletal System Lab skills Public Health Muscular System Integumentary Study of populations System  Highly Competitive ~30 Summer members ~2-4 open spots!!! How to increase my chances? What we expect + want Complete all assignments on time Consistent attendance No cheating (we can tell) Maintain respect PARTICIPATION!!  Q&A 5-10 Minute Passing Period for Questions LESSON TIME!  Function of the Skeleton Support Protection Movement Electrolyte Balance Acid base balance RBC formation Storage of triglycerides Hormone Production  Cartilage & Bone The cells that produce cartilage (chondroblasts) and the cells that produce bone (osteocytes) are both specialized mesenchymal cells. Mesenchymal cells are undifferentiated connective tissue cells, able to become osteoblasts, chondrocytes, and adipocytes. Cartilage Stiff connective tissue, flexible matrix Functions as shock absorption, shape nose/ears, enclose larynx (voice box), trachea (windpipe), and thoracic cavity Found in epiphyseal plate + most joints Contains: Cells: Chondroblasts: Secrete matrix + surround themselves = lacunae  More Areas of Cartilage Joints between bones e.g. the elbows, knees and ankles Ends of the ribs Between the vertebrae in the spine Ears and nose Bronchial tubes or airways Cartilage Cells: Chondrocytes: Chondroblasts in lacunae, slow rates of metabolism + cell division due to solute diffusion through stiff matrix (no blood capillaries) = cartilage heals slowly, secrete extracellular matrix  Cartilage Gels: Hyaline Cartilage is the precursor tissue for bone for -Proteoglycans fetuses (embryonic skeleton) -Glycosaminoglycans -Cartilage -> Bone through Ex: Chondroitin Sulfate - neg. endochondral ossification charged = binds water Matrix = lots of Fibers glycosaminoglycans + collagen fibers -Collagen -Elastic tissue Diff Cartilage types  Types of Cartilage 1. Hyaline Cartilage Most abundant In septum of nose, ribs, and larynx Covered by a fibrous membrane called perichondrium -Perichondrium consists of outer fibrous layer + chondrogenic layer Extracellular matrix is glassy in HYALINE Lacunae connected by canaliculi! Hyaline Cartilage Types of Cartilage 2. Elastic Cartilage Found in epiglottis, larynx, and pinna of the external ear Similar to Hyaline Chondrocytes, cartilage matrix, perichondrium Known for ELASTIC FIBERS = flexible  Types of Cartilage 3. Fibrocartilage Found in meniscus, pupic symphysis, and intervertebral disc Combo of dense regular connective tissue & hyaline cartilage No perichondrium All together!  Growing Cartilage Appositional growth - a process that occurs when new bone matrix is secreted at the bone surface, causing its diameter to increase Interstitial growth - occurs when chondrocytes within the extracellular matrix divide and secrete new matrix. This causes the cartilage to expand from within itself. Appositional Interstitial Practice 1) Which of the following is NOT a function of the human skeletal system? 1. Fatty acid storage 2. Primary glycogen storage 3. Protection of organs 4. Calcium storage 2) Which statement correctly identifies a similarity between cartilage and bone? 1. Both are produced by specialized mesenchymal cells. 2. Both are avascular. 3. Both are sites of hematopoiesis 4. Both are innervated.  More Practice LMAO A B C 4) What structure is the arrow 3) Which tissue makes up the fetal skeleton? pointing at? 1. Perichondrium 2. Periosteum 3. Stratified squamous epithelium 4. Dense connective tissue BONES Types (self explanatory) Compact vs Spongy Bone Spongy Bone - Calcified + hard -Contains trabeculae + spicules -MANY PORES filled w/ bone marrow -Covered by endosteum Compact (dense) bone - denser calcified tissue w/ no spaces -External surfaces of bones Spongy bone has much more surface area exposed to osteoclast action than compact bone does. Therefore, when osteoclasts resorb bone tissue, it comes largely from the spongy bone. Closer look into compact bone Compact bone surrounds central (osteonic) canals ○ Blood vessels and nerves travel thru The bone matrix is deposited in concentric lamellae Osteon = central + surrounding lamellae Structural units of long bones/pillar Haversian canal run thru center Perforating canals / Volkmann's canals run perpendicular The bone as a whole is covered with a tough fibrous periosteum  Quick Review  Bone Cells Osteogenic / osteoprogenitor cells - Stem cells from embryonic mesenchyme. ○ Occur in endosteum and inner layer of periosteum. Osteoblasts - Bone-forming cells. ○ Synthesize organic matter of the bone + promote its mineralization thru secretion of osteoid (osteogenesis). ○ Occur in endosteum and inner layer of the ○ periosteum. ○ Nonmitotic ○ Endocrine function: Secrete osteocalcin - stimulates insulin secretion by the pancreas, limits growth of adipose tissue Bone Cells Osteocytes - Mature bone cells / previous osteoblasts that entrapped themselves in matrix Inside lacunae (sounds familiar?) Connected by canaliculi Have delicate cytoplasmic processes to pass nutrients + chemical signals to each other AND pass metabolic wastes to a blood vessel. Some resorb bone matrix, others deposit it = homeostatic maintenance of bone density + blood concentrations of calcium and phosphate ions Strain sensors!!!!!  Bone Cells Osteoclasts - Bone dissolving cells on bone surface (resorption bays) ○ Osteolysis ○ Independent lineage from osteoblasts, and osteocytes (hematopoietic stem cells) ○ 3-50 nuclei!! ○ Ruffled border, infoldings on plasma membrane = increase bone reabsorption  Practice 3) What cells are unspecialized bone stem 5) What part of compact bone tissue are circular plates of mineralized extracellular matrix of cells derived from mesenchyme? increasing diameter that surrounds a network of a. Osteoprogenitor cells blood vessels and nerves? b. Osteoblasts a. Osteons c. Osteocytes b. Haversian canal d. Osteoclasts c. Concentric lamellae e. None of the above d. Lacunae e. None of the above 4) What cells are huge cells that is a 6) Which of the following statements about spongy result of the fusion of as many as 50 bone tissue is correct? monocytes? a. Spongy bone tissue contains osteons. a. Osteoprogenitor cells b. Spongy bone consists of lamellae that are arranged b. Osteoblasts in a regular pattern of thick columns called trabeculae. c. Osteocytes c. There are macroscopic spaces in spongy bone tissue d. Osteoclasts that consists of yellow bone marrow. e. None of the above d. Spongy bone tissue makes up most of the interior bone tissue of short, flat, sesamoid, and irregularly shaped bones. e. None of the above Practice Label as many as you can! Answer Key  Finale! THANK YOU SO MUCH FOR COMING!! Remember: Excusal forms exist Two assignments due in Microbe & Disease classrooms (hopefully I get done w/ them tmr…) I am posting additional resources for self-study after this lesson!!!!!