Systems Exam 1 Objectives

Explain why stains are used in histology and predict whether common cellular and tissue components will appear basophilic or eosinophilic in H&E sections.

Stains are used to provide basic anatomical structure, shape, color, and clarity

Structures that will stain blue/basophilic are basic or negatively charged (Hematoxylin)

Structures that will stain red/eosinophilic are acidic or positively charged.

Accurately use plane-of-section terminology and explain how lane of section alters the 2D appearance of 3D structures.

How a sample is cue.

Longitudinal, Transverse, oblique, and tangential

Identify major cellular structures visible in H&E sections and relate their appearance and staining properties to underlying organelles and cellular functions.

Basophilic- structures with rRNA, RNA, DNA, nucleic acids

Eosinophilic- Structures with proteins

Nucleus can be:

Euchromatic: dispersed, transcriptionally active

Heterochromatic: condensed, transcriptionally inactive

Recognize common histologic artifacts and distinguish them from normal cellular and tissue structures.

Define connective tissue and explain the functions of connective tissue and the roles of its cells, fibers, and ground substance.

Compare connective tissue types based on cellularity, fiber composition and orientation, and ground substance.

Connective tissue can be loose with low fiber density that allows for diffusion and flexibility. Loose CT is often found around nerves and vessels. Dense CT has high fiber density, high tensile strength, and is used for mechanical forces. Dense CT can be further classified into regular and irregular. Dense regular CT has parallel bundles with high strength in 1 direction. Dense irregular is interwoven in multiple direction and can support stress in multiple directions. CT can be classified as elastic if it contains abundant elastic fibers and collage, this CT can stretch and recoil. CT can be classified as reticular if a fine branching network of reticular fibers is present. White adipose CT is used for storing triglycerides, insulation, and cushioning. This CT is a single large lipid droplet within the cell.

Identify major resident and transient connective tissue cells and relate their appearance to function.

The major resident CT cells are Fibroblasts, macrophages, and mast cells.

The major transient cells are Neutrophils, eosinophils, basophils, lymphocytes, and plasma cells

*Know definitions and identification.

Recognize and classify connective tissues in H&E sections using their characteristic microscopic features.

Be able to identify CT from slide images.

Describe the defining characteristics of epithelium, including polarity, basement membrane, intercellular junctions, surface specializations, and avascularity.

The epithelium is made up of epithelial cells. Epithelial cells are polar which creates apical and basolateral sides. Intercellular junctions hold epithelial cells together and attach the cells to the basement membrane of the epithelium. Surface specializations an be present on either side of the cell. Due to the avascularity of epithelium, nutrient diffusion must occur through other methods. The basement membrane of the epithelium is on the basal side and is made of collagen and contains CT to provide strength.

Compare epithelial junctions based on their location, attachment partner, cytoskeletal association, and primary function.

Know tight junctions, adhesion belt, desmosome, hemidesmosome, and gap junction.

Distinguish the major epithelial surface specializations and modifications based on their apical or basolateral location, structure, cytoskeletal composition, function, and histologic appearance.

Basolateral specializations: infoldings/invaginations

Apical specializations: Microvilli, Stereocilia, Cilia, Cornification

Classify epithelium on H&E sections using cell-layer organization, apical cell shape, and identifying specializations.

Number of cells: simple, stratified, pseudostratified, and transitional

Surface cell shape: squamous, cuboidal, columnar, polyhedral

Specializations: ciliated, with microvilli, with brush border, keratinized, with goblet cells

Distinguish endocrine and exocrine glands and relate their epithelial organization to how secreted products reach their destinations.

Exocrine: secrete product out of the body through ducts. Can be sweat, salivary, intestinal, or uterine. Classified as simple or compound.

Endocrine: secrete product into the blood, no ducts! Can be pituitary, adrenal, thyroid, or parathyroid.

Explain how the epidermis, dermis, and hypodermis organize the integument and support protection, flexibility, and homeostasis

Functions: barrier, protection, temperature regulation, and interaction with the environment.

Layers: Epidermis, dermis, and hypodermis

Explain how epidermal layers, cells, and inclusions create a renewing, protective, keratinized barrier

Know the layers of the epidermis: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.

Epidermal cells: Keratinocytes, melanocytes, Langerhans cells, and Merkel cells

Specializations: cornification, keratohyaline granules, and melanin.

Identify integumentary appendages and receptors and explain how their structure supports secretion, hair growth, and sensation.

Glands: Merocrine (eccrine) sweat glands, apocrine sweat glands, and sebaceous glands

Hair follicles

Receptors: Meissner’s Corpuscle, Pacinian Corpuscle

Classify the major divisions of the nervous system and explain primary functions of each division.

Central-

• Cerebrum: largest, voluntary and cognitive

Subcortical Structures-

• limbic system, thalamus, basal ganglia, substantia nigra, subthalamic nuclei, hypothalamus: memory and sensory input

Cerebellum- regulating movement

Brain Stem- basal regulatory processes, connection between higher brain centers and spinal cord

Spinal Cord- information highway

Peripheral

Sensory System- brings info to CNS

• General visceral afferent, general somatic afferent, special somatic afferent, special visceral afferent

Somatic System- info away from CNS, reflexes

• general somatic efferent

Autonomic System- unconscious control of viscera

• general visceral efferent

  • Sympathetic, parasympathetic, enteric

Trace major somatic motor and sensory pathways through the spinal cord and brain, identify key neurotransmitters, and use pathway organization to localize neurologic lesions.

The Motor System- Originates in the brain in the primary motor cortex. 2 neuron pathway, upper motor neuron in primary motor cortex, lower motor neuron in anterior horn of the spinal cord. Neurotransmitters: ACh (excitatory/contraction. primary), Glutamate (excitatory), Glycine (inhibitory). LMN signs occur at the level of the lesion. UMN signs occurs below.

The Sensory System- Always enters through the dorsal root. Neuron cell body is in dorsal root ganglion. Three different pathways: Tactile and proprioceptive, tactile and nociceptive, and balance and posture.

• Tactile & Proprioceptive: Posterior Funiculus / Medial Lemniscal Pathway

  • Crosses over in the brain stem (late).

  • 3 neuron pathway

• Tactile & Nociceptive: Anterolateral / Ventrolateral Pathway

  • Crosses over after dorsal root ganglia (early).

  • 3 neuron system

• Balance/posture: Spinocerebellar pathway

  • 2 neuron system

Lesions: ???

Compare the organization and neurotransmitters of the automatic pathways and predict organ responses and signs of failure.

Both:

• 2 neuron pathways

• Use ACh as an NT

• Have a push-pull relationship with the other

Sympathetic:

• Short presnaptic neuro and a long post synaptic neuron

• Originates in the thoracolumbar region of the lateral horn of the spinal cord

• Presynaptic neuron sends axon out the ventral root into the sympathetic chain ganglia (synapse)

• Postsynaptic neuron sends axon out the chain ganglia to target organ.

• Postsynaptic NT is norepinephrine

Parasympathetic

• Long presynaptic neuron and short postsynaptic neuron

• Originates in the brainstem and travels through the vagus nerve

• Presynaptic neuron is in the brainstem or the sacral spinal cord

• Postsynaptic neuron is at the target organ

Identify the major components of neural tissue and relate their structures, locations, and terminology to their basic functions.

Identify peripheral nerves on H&E sections and relate their connective-tissue layers, nerve fibers, and schwann cells to function.

Identify peripheral neurons and ganglia on H&E sections and relate their major cellular components to function

Identify major spinal cord structures on H&E sections and relate their cellular and regional organization to function.

Identify cerebellum on H&E sections and relate cerebellar microanatomy to its role in coordination motor activity.

Identify major structures of the cerebrum and relate cortical organization, specialization, and ventricular anatomy to function.

Identify the cells, extracellular matrix, and connective tissue covering of cartilage and describe their microanatomic organization.

Distinguish hyaline, elastic, and fibrocartilage based on their histologic features and relate their structure to location and function

Compare interstitial and appositional cartilage growth and identify where each occurs.

Identify the cells, extracellular matrix, and connective tissue linings of bone and describe their microanatomic organization

Compare the microscopic organization of compact and spongey bone.

Compare intramembranous and endochondral ossification, identify where they occur, and describe the organization of the growth plate.

Distinguish woven and lamellar bone and relate their organization to bone formation, maturation, and repair.

Explain how bone matrix composition, and specialized bone cells determine bone strength, formation, maintenance, and resorption.

Explain how bone remodeling repairs microdamage and adapts bone structure to mechanical loading.

Explain how bone provides rapid calcium buffering and endocrine regulation to help maintain extracellular calcium homeostasis.

Explain how bone functions as an endocrine organ through osteocalcin, FGF23, and regulation of the hematopoietic stem-cell niche.

Organize skeletal muscle from whole muscle to myofilament and relate each level to force production.

Identify sarcomere landmarks and predict which dimensions change during shortening.

Explain the functions of actin, myosin, titin, nebulin, troponin, tropomyosin, and connective-tissue sheaths.

Use the sliding-filament model to predict structural consequences of altered filament overlap.

Trace the casual sequence from motor-neuron AP to skeletal-muscle relaxation.

Explain ACh release, the end-plate potential, and initiation of a muscle AP.

Relate T-tubule depolarization to DHPR-RyR1 coupling and SR Ca2+.

Describe Ca2+ dependent thin filament activation and each step of the cross-bridge cycle

Explain how skeletal muscle force is regulated by motor unit recruitment and rate coding, including the size principle and temporal summation.

Describe the relationship between action potentials, intracellular Ca2+, cross-bridge cycling, and force development, and explain the physiological basis of twitch summation and tetanus.

Compare small and large motor units with respect to motor unit size, recruitment order, precision, and force production.

Differentiate muscle spindles from Golgi tendon organs in terms of their location, stimulus, sensory innervation, and physiological function. Muscle spindles monitor muscle length and changes in length, whereas GTOs respond strongly to contraction and changes in contractile force.

Interpret the skeletal muscle length-tension relationship and explain how actin-myosin overlap determines force production across the ascending limb, plateau, and descending limb of the curve.

Distinguish isometric, concentric, and eccentric.

Interpret force-velocity and power-velocity relations.

Compare ATP buffering, glycolytic, and oxidative ATP supply across time scales.

Relate fiber phenotype to sprint, endurance, and postural tasks across species.

Explain fatigue as task-specific and multifactorial, and differentiate fatigue from weakness and muscle damage.

Compare skeletal, cardiac, and smooth muscle activation, Ca2+ sources, regulatory proteins, and control.

Explain cardiac Ca2+-induced Ca2+ release and why cardiac muscle cannot be tetanized physiologically.

Use length-dependent activation to explain the Frank–Starling mechanism conceptually.

Explain smooth-muscle Ca2+–calmodulin–MLCK regulation, latch behavior, and mechanisms of relaxation.