Anatomy Lecture

1. Anatomy Lecture Comprehensive Review

2. Cell Membrane • The plasma (cell) membrane is made up of two layers of molecules = PHOSPHOLIPIDS. • Phospholipids are amphipathic molecules. • That means they have a polar region and a non-polar region. • The polar region consists of PHOSPHATE HEADS and this region is considered to be HYDROPHILIC (likes water). • The non-polar region of the cell membrane consists of FATTY ACID TAILS and this region is considered to be HYPDROPHOBIC(repels water).

3. Cell Membrane • The cell membrane is semi-permeable to allow only certain things into and out of the cell. • Functions of the Plasma Membrane: • Movement of materials into and out of cell • Acts as a barrier to the external environment • Acts as a site for receiving signals from the rest of the body • Acts as a site for holding the cell in place

4. Golgi Complex • The Golgi complex is like a Fed-Ex center that packages and ships the proteins from the ribosomes. • The proteins from the ribosomes enter the Golgi channels from the RER. • While in the Golgi complex, the proteins are modified and prepared for transport out of the cell.

5. Mitochondria • Mitochondria are considered the smallest living units in the body because they can make their own energy (ATP). Cells have hundreds of mitochondria. • Function of mitochondria is to make most of the cell’s ATP, which is cellular energy (ATP is an energy source). • Some ATP is made in the cytosol, but most is made in the mitochondria. • NOTE: Mitochondria must have OXYGEN to convert nutrients to ATP for energy.

6. AMINO ACIDS • AMINO ACIDS are MONOMERS (building blocks) of protein. They are tiny carbon molecules, made of just a carbon atom and a few other atoms. There are only about 12 types of amino acids. They are like beads on a necklace. How they are arranged on the string determines the type of necklace. Each bead is an amino acid, and the whole necklace is the protein. A bunch of the same types of necklaces (proteins) woven together makes up our tissues.

7. Nucleus • When GENE TRANSCRIPTION occurs, it is characterized by mRNA SYNTHESIS (messenger RNA is synthesized). • This occurs in the nucleus. • The mRNA then exits the nucleus and goes to the cytoplasm. • When TRANSLATION occurs, it is characterized by PROTEIN SYNTHESIS. • This occurs in the cytoplasm.

8. REVIEW OF GENETICS • The nucleus of the typical (diploid) cells of the body have 46 chromosomes . Each gamete (ovum or sperm) has 23 chromosomes. • A chromosome is a double-stranded string of DNA. • DNA is made of a string of molecules called nucleic acids. There are only 4 different nucleic acids: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). • Each A, T, G, or C on one strand of DNA is paired to its counterpart on the other strand of DNA. • Adenine (A) only pairs with Thymine (T), and Guanine (G) only pairs with Cytosine (C). • When they pair up, they are called base pairs. The double strand of DNA looks like a ladder. It is then twisted into a shape called a helix. • Therefore, DNA is a double-stranded helix.

9. Tissues and Organs TISSUE: A group of cells, usually similar, which share a particular function. • Each ORGAN is made up of one or more tissues.

10. Integument system • ARRECTOR PILLI: tiny muscles that make the hairs stand up during “goosebumps”. • HAIR PAPILLAE: what is destroyed by electrolysis, so hair won’t grow back. • The HAIR MATRIX is the leading edge of the papillae. It is actually skin cells (keratocytes) which are rapidly dividing. When they die, the new ones push them out, forming the hair. Hair is just dead skin cells. The HAIR ROOT is just the base of the hair. • The hair matrix is the part of the follicle that is the site of hair growth and the location of the melanocytes that determine hair color. • Hair that goes grey has lost its melanin pigment.

11. Layers of the Epidermis • Stratum corneum (most superficial layer of epidermis) • Stratum lucidum (only in thick skin) • Stratum granulosum (cells start to die here) • Stratum spinosum • Stratum basale (the deepest layer of epidermis; cells are reproducing only here)

12. Skin Cancer This is the most common cancer in the USA, and its major risk factor is exposure to ultraviolet light. 1) BASAL CELL CARCINOMA: Cancer of the blood vessels. Almost never metastasizes or crosses the basement membrane Looks like shiny nodules 2) SQUAMOUS CELL CARCINOMA 25% of all cancers Will metastasize if not treated. 3) MELANOMA: cancer of the melanocytes of the epidermis Highly metastatic. Asymmetrical, sharp but irregular borders and edges Not uniform in color.

13. BURNS • FIRST DEGREE: Minor burn to the epidermis; sunburn • SECOND DEGREE: Dermis separates from epidermis; blister • THIRD DEGREE: Hypodermis is burned. (most severe type of burn) • KELOID: Thick, red, painful scars • HEMANGIOMA: enlargement of the lining of blood vessels, and is treated with lasers

14. Piebaldism: a rare autosomal dominant disorder of melanocyte development, causing a congenital white patch of hair.

15. Gross Anatomy of Bones TWO TYPES OF BONE TISSUE • Compact bone – dense outer layer of bone • Found in the diaphysis (shaft) of long bones • Spongy (cancellous) bone – internal network of bone • Found in the epiphysis (ends) of bones • Osteomalacia: Rickets caused by lack of Vitamin D • Achondroplasia: type of dwarfism • Chondromalacia: cartilage rubbing off, usually under the patella of active people.

16. CLASSIFICATION OF FRACTURES • SIMPLE (CLOSED) • Skin is not broken • May just require a cast • COMPOUND (OPEN) • Bone has broken through the skin • Increased chance of infections, which can be life-threatening. • Requires surgery, hospitalization and IV antibiotics

17. CLASSIFICATION OF FRACTURES • INCOMPLETE • Only one side of the bone is broken • COMPLETE • Both sides of bone is broken • DISPLACED: The bone fragments don’t line up • Produces new and abnormal bone arrangements • Non-DISPLACED: The bone fragments stay lined up

18. TYPES OF FRACTURES • COMMINUTED: The most serious of the closed fractures; bone shatters into many small pieces. Bone graft might be needed. • SPIRAL: Bone was twisted. • GREENSTICK: most common in children • COMPRESSION: bone is crushed, like the vertebrae in osteoporosis. • STRESS: least serious, get tiny, almost invisible breaks. • COMPOUND (open) FRACTURES: Bone breaks and goes through skin. Increased chance of infections, which can be life-threatening. • SIMPLE (closed) FRACTURES: Skin is not broken. • PATHOLOGICAL FRACTURE: When the bone (especially the hip bone of someone with osteoporosis) breaks first, then the patient falls.

19. CLASSIFICATION OF Joints: Two ways • 1. What type of movement does the joint allow? • No movement, limited movement, free movement • 2. What tissue joins the bones? • Fibrous Joints • Fibrous connective tissue (dense regular CT) • suture, tooth, ligament • Cartilaginous Joints • Fibrocartilage (vertebral discs, pubic symphysis) • Hyaline cartilage, no capsule (epiphyseal plate, costal cart) • Synovial: Hyaline cartilage with a capsule

20. Types of Movement • Synarthrotic • immoveable, allows no movement • Amphiarthrotic • allows only limited movement • Diarthrotic • freely moveable

21. Cartilaginous Joints • A cartilaginous joint is two bones joined by cartilage. The cartilage is either fibrocartilage or hyaline cartilage. • Fibrocartilage joints (symphyses) are amphiarthrotic (slightly moveable). • Examples are intervertebral discs and the pubic symphysis • Hyaline cartilage joints (synchondroses) are synarthrotic (immovable). • Examples are epiphyseal plates and costal cartilages • Therefore, one type of cartilaginous joint is slightly moveable (fibrocartilage) and one type of cartilaginous joint is immovable (hyaline)

22. LIGAMENTS • The joint capsule alone is not strong enough, so there are reinforcing LIGAMENTS, which provide most of the strength of holding the bones to bones. They are dense regular connective tissue. • In the knee joint, the collateral ligaments are the main ligaments that keep the knee from moving medially to laterally.

23. LIGAMENTS • Ligaments take a long time to heal if torn because they do not have blood vessels of their own, like bones do. They already have enough fibroblasts and collagen, though, so they eventually can heal. It is better to break a bone than tear a ligament because bones have a better blood supply and heal faster. • SPRAINS: are tears in a ligament, and are fairly serious. When a ligament is sprained, it can take 6 months to heal, and may even need surgery. Even with a partial tear, you have to be careful. • STRAIN: is a tear in a muscle, and is not as bad because it has good circulation and heals faster. If you can walk on it and it heals in a couple of days, it’s a strain.

24. Skeletal Muscle • For skeletal muscle to contract, a neuron must first release a chemical called acetylcholine onto the region known as the endplate. • Calcium is also needed for muscle contraction. • The nerve signal is called an ACTION POTENTIAL. • It causes a release of calcium from the muscle fiber, which causes contraction.

25. Don’t confuse these terms! MUSCLE FASCICLE: a group of muscle fibers, surrounded by perimysium. MUSCLE FIBER: a single muscle cell MYOFIBRIL: a long organelle inside a muscle fiber, contains actin and myosin myofilaments. MYOFILAMENTS: these are proteins, and there are two types: actin (with troponin and tropomyosin) and myosin. The myofilament is the lowest level of organization that is composed of actin, myosin, troponin, and tropomyosin proteins. Therefore, a myofilament is part of a myofibril, which is inside a muscle fiber, which is inside a muscle fascicle.

26. MECHANISM OF CONTRACTION The Sliding Filament Theory • Contraction results as the myosin heads of the thick filaments attach like hooks to the thin actin filaments at both ends of the sarcomere and pull the thin filaments toward the center of the sarcomere. • The myosin head is like a hook with a hinge. After a myosin head pivots at its hinge, it draws the actin closer, then lets go, springs up again to grab the actin filament again, pulls it closer, and it keeps repeating this until the entire actin filament has been drawn in as far as it can go. • The sites where the myosin heads hook onto the actin are called cross-bridges.

27. Muscle Contraction • TROPONIN is a complex of three proteins. • TROPOMYOSIN is a single protein. • Both troponin and tropomyosin cover the ACTIN filament when the muscle is relaxed. • PHRENIC NERVE: controls contraction rate of the diaphragm.

28. ATP and Creatine Phosphate • What do we do when we run out of ATP? • Muscle fibers cannot stockpile ATP in preparation for future periods of activity. • However, they can store another high energy molecule called creatine phosphate, which is the storage form of ATP. • Creatine phosphate is made from the excess ATP that we accumulate when we are resting. • During short periods of intense exercise, the small reserves of ATP existing in a cell are used first. • Then creatinine phosphate is broken down to produce ATP.

29. Muscle Disease • MUSCULAR DYSTROPHY • Genetic lack of the protein DISTROPHIN. • The muscle cell won’t contract.

30. Bone Cells • Osteoblast (makes bone) • Osteocyte (mature bone cell) • Osteoclast (reabsorbs bone) • Bone Infection = osteomyelitis

31. Osteon • Osteon: The functional unit of compact bone. • osteocytes The mature bone cells which are trapped in the matrix and help to maintain it • lacunae The pockets or cavities in which the osteocytes live and are trapped • canaliculi The “tiny channels” for the legs of each star-shaped osteocyte. Canuliculi allow for diffusion of nutrients and wastes to the other osteocytes. • lamellae The circular and concentric layers formed by the osteocyte matrix because they sit next to each other in circles.

32. ARTHRITIS • OSTEOARTHRITIS: common in older people. The articular cartilage begins to break down, and bone spurs start to grow. • RHEUMATOID ARTHRITIS: It’s an autoimmune disease where body attacks and destroys the cartilage in synovial joints. It is NOT known for having spurs, like osteoarthritis. • GOUTY ARTHRITIS (gout). Caused by eating too much red meat or protein. The breakdown product is urea, and acid, which causes uric acid crystals in the cooler areas of the body, especially big toes.

33. Types of Glial Cells 1. OLIGODENDROCYTES (“few branches”). They are found in the CNS, are very large and complex cells. Oligodendrocytes form MYELIN SHEATHS. This sheath is a covering around an axon to speed up the nerve conduction.

34. Types of Glial Cells 2. SCHWANN CELL is another cell that forms myelin sheaths, but in the PNS. Each cell only forms one myelin sheath.

35. The action potential jumps from one Node of Ranvier (the bare area) to the next Node, skipping the myelin that is between the bare areas). This speeds up the overall nerve conduction. • Therefore, a myelinated axon conducts impulses faster than an unmyelinated axon. • Why aren’t all neurons myelinated? Isn’t it good for everything to be faster? • No, myelin is a living cell, so it uses nutrients! • We’d better save the myelin for where we need it.

36. Neuron Disease MULTIPLE SCLEROSIS is an autoimmune disease where the oligodendrocytes (the myelin sheaths) are destroyed (demyelination), interfering with the neuron functions in the CNS. Oligodendrocytes cannot regenerate. MS is the most common neurological disease of young adults. Starts to manifest in late teens and early 20’s. It progresses to paralysis and sometimes death. One in 1000 people get it. There are treatments, but no cure.

37. V. Trigeminal Nerve • This is the main sensory nerve of the face. It has a large branch that passes through the foramen ovale of the skull. It has three parts. • When a dentist numbs the lower teeth, he injects the mandibular branch. For the upper teeth, he injects the maxillary branch. • The superior branch is the opthalmic branch. • Problems with CN-V are called TRIGEMINAL NEURALGIA, which is excruciating pain in the face from nerve inflammation.

38. VII Facial Nerve • This is the main motor nerve of the face. It innervates the muscles of facial expression. • A person who cannot blink or smile may have damage to this nerve. • Someone with a damaged facial nerve can not easily taste sweet, sour, or salty substances. • It also supplies parasympathetic innervation to most salivary glands. • BELL’S PALSY is damage of the facial nerve causing paralysis on one side. The nerves swell from infection by herpes simplex virus, but only the motor nerves are involved, not the sensory, so it’s painless. Needs to be distinguished from a stroke. . VIDEO

39. IX: GLOSSOPHARYNGEAL • Along with CN X, the Glossopharyngeal nerve carries information from the baroreceptors in the head and neck to the brainstem.

40. X. Vagus Nerve The only cranial nerve that “Wanders” into thorax and abdomen Table 14.2

41. Pre-Central Gyrus • There is a precise map of the different body parts in the pre-central gyrus. • This map is called a motor homunculus (Latin: little man) • Not all body parts are equally represented by cell density in the motor area in proportion to their size in the body. • Lips, parts of the face and hands enjoy especially large areas of cells in the motor area. • The face region of the homunculus is large so we can have many facial expressions. The hands and tongue are large, indicating that we have many fine motor skills in those areas as well.

42. Sensory Tracts • Sensory signals go to the brain via a TRACT. • A tract is a collection of axons inside the central nervous system.

43. VISCERAL (“organ”) SENSES • A visceral nerve innervates involuntary effectors (smooth muscles in organs). • A somatic nerve innervates voluntary effectors (skeletal muscle).

44. Brain Diseases • HYDROCEPHALY • This is usually congenital, caused by a blockage of the cerebral aqueduct. So the CSF is made but can’t leave, and the brain gets expanded. • MENINGITIS • This is when the meninges become infected. Can be caused from virus (not that bad) or bacteria (can be fatal). The main symptom is a headache. • ENCEPHALITIS • This is infection of the brain. It can be caused by mosquito-borne illnesses, or bacteria. Treatment is to remove a piece of the skull bone to allow the swelling.

45. Auditory Association Area • The auditory association area contains two special regions • BROCA'S AREA is a region of the brain that allows for speech. • Injury (stroke) in this location causes impairment of speaking certain words. They know what they want to say, they just cannot get the words out. Not being able to speak at all is called aphasia. • WERNICKE’S AREA is the region of the brain that allows understanding of words. • It does not affect a person’s speech. • They can say what they want to, but they cannot comprehend someone else’s speech.

46. Peripheral Nerve Damage Carpel Tunnel Syndrome

47. Peripheral Nerve Damage • SCIATICA • Inflamed sciatic nerve • NEUROMA • Inflamed nerve in the ball of the foot • Often caused from wearing high heels

48. Eye Disorders PRESBYOPIA (“old eyes”). Occurs around age 45-50. The lens cannot accommodate. HYPEROPIA (far-sighted) eyes are too short; MYOPIA (nearsighted) CATARACTS. Clouding of the lens. RETINAL DETACHMENT ASTIGMATISM is when the cornea has an irregular shape. MACULAR DEGENERATION: the most common cause of blindness in the US. It’s due to bleeding in the eye, causing scar tissue. DIABETIC RETINOPATHY: the high sugar levels destroy the photoreceptors in the retina. GLAUCOMA: increased pressure within the anterior chamber of the eye. It leads to blindness. AMBLYOPIA = Lazy Eye.

49. Ear Disorders • VERTIGO • Inflammation of the semi-circular canals. • Gives you a sense of motion when you’re not moving = (dizziness).

50. Hematocrit • A quick screening test for anemia is the hematocrit. • A drop of blood is drawn up a small glass capillary tube and the tube is centrifuged to pack the red blood cells at the bottom with the plasma on top. • The hematocrit is the ratio of packed red blood cells to total blood volume. • Normal is 46% for men and 38% for women.