Summer 24 Histology Exam 2 Study Guide PDF

Summer 24 Histology Exam 2 study guide Nervous system Glial cells – the names and the functions Also called neuroglia (supporting cells) 10x more abundant than neurons in brain Support and protect neurons Astrocytes o Supply neuronal mitochondria and raw materi...

Summer 24 Histology Exam 2 study guide Nervous system Glial cells – the names and the functions Also called neuroglia (supporting cells) 10x more abundant than neurons in brain Support and protect neurons Astrocytes o Supply neuronal mitochondria and raw materials for neurotransmitters o CNS o Provides structural support, participates in BBB, materials for NT’s o Foot processes bind to capillaries and neurons Oligodendrocytes o PNS o Makes myelin in CNS Ependymal cells o CNS o Lines cavities of CNS Microglial cell o Macrophages o CNS o Eats up debris and dead cells and participate in immune response for infections of the CNS Schwann cells o CNS o Makes myelin in the PNS Covering of nerves Endoneurium- thin loose sleeve of loose connective tissue surrounding each axon o Allows presence of tissue fluid required for creation of electrical impulses in between each axon and space for capillaries to provide them w oxygen Perineurium-neurons are bundled together into fascicles, which are then encased in another, thicker, layer of connective tissue Epineurium- final, strongest and densest layer, envelopes several groups of fascicles o Provides reinforcement to the nerve Muscles Salient features of each type of muscle tissue Cardiac muscle o Intercalated discs glue adjacent cells together  o Branched o Gap junction o Sarcoplasmic reticulum is kind of sparce o Makes up heart o Strong, quick continuous involuntary contraction o striated Skeletal muscle o Has multiple peripheral nuclei o Cylindrical o Strong, quick discontinuous voluntary contraction o Striated Smooth muscle o No striations o Spindle shaped o Weak, slow involuntary contraction Location of muscle fibers Smooth muscle o Present in walls of hollow organs ▪ Such as intestine and uterus o Also present in walls of larger blood vessels and in the eye o Walls of hollow organs and blood vessels Cardiac muscle o Thick middle layer of the heart o Heart wall Skeletal muscle o Muscles attached to the skeleton o Attached to bones via tendons o Near bones Sarcomere and the regions within a sarcomere Sarco- flesh When muscles contract, sarcomeres shorten Actin filaments get pulled toward each other. The distance between the Z line shortens, and the H band disappears Skeletal muscle with A bands, I bands, and Z lines Intercalated discs, where they are found and what is found within them Glue adjacent cells together In cardiac muscle Contains gap junctions and desmosomes for depolarization and muscle contraction Myofiber, vs myofilament, vs myofibril Myofiber o Each fascicle is composed of a bunch of muscle cells Myofilament o Makes super-specific repeating pattern of light and dark bands  Myofibril o Each muscle cell contains a bunch of these o Have stripes (striations) Heart Layers of the heart Endocardium o Endothelial lining with a supporting layer of fibroelastic connective tissue and deeper connective tissue layer continuous with the myocardium called the subendothelial layer o ***Contains Purkinje fiber network*** Myocardium o Cardiac muscle fibers arranged in spirals around the heart chambers o Myocardium of left ventricle is thicker due to more force used during contraction Epicardium o (Simple squamous mesothelium) corresponds to visceral pericardium o Secretes serous fluid to decrease friction when beating o Outside of the heart Lymphatics The lamina propria is rich in lymphatic tissue (MALT) mucosa Mucosa- epithelial lining with underlying lamina propria of loose connective tissue rich in blood vessels, lymphatics, lymphocytes, smooth muscle cells and glands Purkinje fiber location In the subendothelial layer Blood vessels: differentiate capillaries from arteries and veins, know differences between tunica media and tunica adventitia in arteries vs veins Capillaries- exchange metabolites by diffusion to and from cells Arteries- conduct blood from heart and with elastic recoil help move blood forward under steady pressure Veins- collect blood from venules, carry blood to larger veins with no backflow Tunica media- concentric layers of smooth muscle interposed between elastic fibers, reticular fibers and proteoglycans o In arteries-external elastic lamina o Vasa vasorum- arterioles, capillaries and venules Tunica adventitia- connective tissue (mainly type 1 collagen and elastic fibers) o Continuous and bound to stroma of organ through which it traverses o Vasa vasorum o ANS unmyelinated vasomotor nerves Which vessels have valves Veins have valves that open and close What substances are secreted by blood vessels  Endothelium Vascular tone cells Local immune response Blood Composition of whole blood Specialized connective tissue consisting of o Formed elements (blood cells) o Plasma-liquid portion (ECM) o Removal of cells and most proteins from plasma generates serum Distributing vehicle for gases, nutrients, waste by products of cellular metabolism, etc. Granulocytes vs agranulocytes Granulocytes- abundant granules (Lysosome); polymorphic nucleic with 2 or more distinct lobes o Neutrophils o Eosinophils o Basophils Agranulocytes- lack granules but still contain lysosomes o Lymphocytes- spherical nucleus that is indented but not lobulated o Monocytes- leave blood stream and become macrophages, phagocytes Platelets AKA thrombocytes, very small, non-nucleated membrane bound cell fragments that originate from bone marrow cells called megalokaryocytes A sparce glycocalyx surrounds which helps with adhesion Their role is to contain blood loss (hemostasis) Know about red blood cells Biconcave Hemoglobin Transportation of Hg Hematopoeitin What protein is most abundant in the plasma Albumin Functions of the lymphocytes WBC Immunological surveillance Recognizing and destroying abnormal cells when they appear in peripheral tissues Help your body’s immune system fight cancer and foreign viruses and bacteria GI Epithelial types in the GI system, from mouth to anus Musoca  o Epithelial lining with underlying lamina propria of loose connective tissue rich in blood vessels, lymphatics, lymphocytes, smooth muscle cells and glands o There is a thin muscularis muscluae layer separating the mucosa from the submucosa Submucosa o Denser connective tissue with larger blood vessels and submucosal plexus (Messiner) plexus of autonomic nerves as well as significant lymphoid tissue Muscularis layer o Smooth muscle arranged in 2 or more layers-Internal (closer to the lumen that has a circular fiber arrangement) and external layer in a longitudinal arrangement o The myenteric (Auerbach) plexus is between these layers o Autonomic nerves Serosa o Thin sheet of loose connective tissue rich in blood vessels covered in a sheet of mesothelium that secretes serous fluid for lubrication o The serosa of small and large intestine is continuous with mesentery and peritoneum Know the projections in the GI system and what they are made of Types of muscle in the esophagus Muscular tube connecting pharynx to stomach 4 layers of GIT establish here Mucosa has nonkeratinized stratified squamous epithelium Submucosa has mucous secreting glands Muscularis- upper 1/3rd of esophagus is skeletal muscle; lower 1/3rd is smooth muscle; middle is a mix of both How many layers of muscle in esophagus, stomach, small intestine and large intestine Esophagus- 2 Stomach- 3 Small intestine- 2 Large intestine- 4 MALT Large intestine Mucosa associated lymphatic tissue o Due to large bacterial population What is released from each type of cell in the gastric pits, and what its function is. Surface mucous cell- secretes alkaline fluid containing mucin Mucous neck cell- secretes acidic fluid containing mucin Parietal cell- secretes intrinsic factor and hydrochloric acid Chief cells- secretes pepsinogen and gastric lipase G cell- enteroendocrine cells that secrete gastrin into the blood Respiratory system Respiratory epithelium Most of the nasal cavities and conduction portion of the system is lined with. Mucosa having ciliated pseudostratified columnar epithelium o commonly called “respiratory epithelium” Tracheobronchial tree, Presences of cartilage or not, and the types of epithelium found in each region Trachea- lined with respiratory mucosa with pseudostratified ciliated epithelium o lined with C-shaped rings of hyaline cartilage which help to keep airway open o lots of seromucous glands Trachea divides into 2 primary bronchi which enter each lung o Further subdividing into 2nd-ary and tertiary bronchi o Even smaller divisions continue as bronchioles then terminal bronchioles followed by respiratory bronchioles o Final divisions of tree are alveolar ducts followed by alveoli o We see several changes in epithelium as the primary bronchi branch and the diameter of each branch decreases What type of tissue makes up the alveoli Types 1 and 2 alveolar cells (pneumocytes) No muscles or skeletal support (but with network of elastic and reticular fibers) Sites of all gas exchange; surfactant from type 2 pneumocytes; dust cells Know about goblet cells Intestinal mucosal epithelial cells that serve as the primary site for nutrient digestion and mucosal absorption Primary function- synthesize and secrete mucus Primary secretory cell in superficial epithelium of large airways Secrete mucin Skin Epidermis- how many layers make it up, and what order the layers are in from basal to apical Stratum Basale Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum Know defining characteristics of the layers of the epidermis Basale (germinativum) o Deepest w a single layer of cuboidal to low columnar cells ▪ Keratinocytes- generate keratin ▪ Melanocytes- generate melanin using organelles called melanosomes  ▪ Tactile cells- Merkel cells which are for sensitive touch Spinosum o “spiny layer” seen as cellular processes linking cells together (desmosomes) ▪ Several layers of polygonal keratinocytes ▪ Daughter cells from basal pushed into this layer ▪ Dendritic cells (Langerhans) are present in spinosum and granulosum → initiate immune response as they are sensitive to epidermal pathogens Granulosum o Consists of 3-5 layers of flattened cells, now undergoing the terminal differentiation process of keratinization o Their cytoplasm is filled w intensely basophilic massed called keratohyalin granules Corneum o Most superficial layer ▪ Protects from water loss, friction and microbial invasion. Consists of flattened, terminally differentiated cells which are slowly lost Where the different nerve receptors are located (dermis vs epidermis vs subcutaneous tissue) Epidermis o Tactile Cell: ▪ Merkel Cell-Sensitive touch In basal cell layer of epidermis Found in both skin and mucosal tissue. Increased in palms, finger pads, feet, and plantar surface Dermis ▪ Meissner Corpuscle- only in thick skin Fine discriminative touch and vibrations In finger tips this is what would allow us to read braillae ▪ Pacinian Corpuscle Sensory receptors for vibration and deep pressure and are essential for proprioception Layers of the dermis (papillary vs reticular and what is found in each) Thin papillary layers which includes dermal papillae and consists of loose connective tissue with types 1 and 3 collagen fibers. Mast cells, fibroblasts and dendritic cells Thick reticular layers (deeper) consist of dense irregular connective tissue, mainly type 1 collagen Subpapillary plexus- microvascular plexus with capillary branches that extends into the dermal papillae and form a rich nutritive network below the epidermis AVASCULAR GU Epithelium from ureter to external urethral orifice Ureters are muscular tubes that connect the kidneys to the urinary bladder The wall of the ureter is composed of 3 layers” inner mucosa, middle muscularis, and outer adventitia/serosa Mucosa has a transitional epithelium that allows the ureters to stretch and accommodate urine flow w out leakage (cuboidal to squamous in shape) Urinary bladder is a muscular sac-like organ that stores urine until it is eliminated from the body Its wall is composed of several layers, including the inner mucosa lined by transitional epithelium, a muscular layer called detrusor muscle, and an outer adventitia or serosa Muscle of the urinary bladder Ureters o Muscular tubes that connect kidneys to urinary bladder Functional unit of the kidney The basic functional unit of the kidney is the nephron o Consists of a renal corpuscle (glomerulus and Bowman’s capsule) and a renal tubule Types of capillaries in the kidney (continuous, fenestrated or sinusoid Continuous- larger openings (fenestrations) between the cells that allow the quick exchange of substances Fenestrated- exist in and near the nephrons (the filtering units) o Work with the rest of your circulatory system to move nutrients, waste and oxygen through your body o Essential role in helping kidneys filter waste and create urine Sinusoid- allow for the exchange of large molecules, even cells o Have many larger gaps in their capillary wall, in addition to pores and small gaps