Cell Membranes, Cell Types, and Tissues

Flashcards covering cell membrane composition, organelle classification, epithelial, connective, muscle, and nerve tissue structures, and general organ system anatomy based on lecture notes.

Which organelles are classified as membrane-bound within eukaryotic cells?

Plasma membrane, Nucleus, Endoplasmic Reticulum, Golgi Apparatus, Lysosomes, Endosomes, Peroxisomes, and Mitochondria.

Which organelles and structural elements are classified as non-membrane bound?

Ribosomes, Proteasomes, Cytoskeleton Elements, Centrioles and Basal Bodies, Cilia, and Flagella.

What is the main phospholipid found in most animal cell membranes and what is its backbone structure?

Glycerophospholipid, which contains a three carbon glycerol backbone.

What term describes molecules like membrane lipids that contain both hydrophobic and hydrophilic components?

Amphipathic.

How many major phospholipids are present in mammalian plasma membranes?

Four major phospholipids.

What are the primary protein components of cell membranes?

Integral proteins (transmembrane, multipass) and peripheral proteins (extracellular and cytosolic).

What specialized cell membrane microdomains function as "signaling platforms"?

Lipid rafts.

What are three main functional types of channel proteins mentioned in the cell membrane lecture?

Voltage-gated proteins, ligand-gated proteins, and mechanically-gated proteins.

What are three examples of pumps and carrier proteins given in the lecture?

$\text{Na}^+\text{-K}^+$ pump, $\text{Ca}^{++}$ pumps, and glucose transporter.

On which days of early embryogenesis does gastrulation occur?

Days 15 and 16.

What are the three germ layers generated during gastrulation and their spatial positions?

Ectoderm externally, mesoderm in between, and endoderm internally.

What are the four major tissue types present in the human body?

Epithelial tissue, Connective tissue, Muscle tissue, and Nerve tissue.

Approximately how many specialized cell types are found in the human body?

$\sim 200$ specialized cells.

What is the specific term for epithelial tissue that lines blood vessels?

Endothelium.

What is the specific term for the epithelial tissue layer of the skin?

Epidermis.

What are the seven primary functions of epithelial tissue listed in the lecture?

Protection, absorption, secretion, excretory, lubrication, sensory, and reproduction.

From which germ layers are epithelial tissues derived?

All three germ layers (ectoderm, mesoderm, and endoderm).

What are three structural differentiations found on the apical domain of polarized epithelial cells?

Cilia, microvilli, or stereocilia.

What layer is secreted by epithelial cells to form the interface with underlying supportive tissues?

The basal lamina.

By what light microscopy technique is the basement membrane visible as a positive layer?

PAS-positive layer (Periodic acid-Schiff).

How are exocrine and endocrine epithelial glands structurally distinguished?

Exocrine glands are organized into units that secrete into a tubular network of ducts, while endocrine glands lose duct cells and secrete directly into the bloodstream.

In stratified epithelial tissues, where does cell mitosis exclusively take place?

Mitosis only occurs in the cells at the basal layer.

What are the specific medical terms for a tumor of epithelial origin and a tumor of glandular epithelial origin?

Carcinoma is a tumor of epithelial origin; adenocarcinoma is a tumor of glandular epithelial origin.

What are the two major structural components that make up connective tissue?

Cells and extracellular matrix (consisting of fibers and ground substance).

How are parenchyma and stroma distinguished in tissues?

Parenchyma refers to cells that perform the major function of the organ, while stroma connects and supports other elements of the tissue.

Which basic tissue type is primarily of mesodermal origin and contains blood vessels and nerves with the exception of cartilage?

Connective tissue.

How is connective tissue proper classified?

1. Loose connective tissue; 2. Dense connective tissue (dense irregular and dense regular).

What are the four types of specialized connective tissue?

Cartilage, Bone, Blood, and Adipose.

Which resident cell types are found within connective tissue?

Fibroblasts, adipocytes, pericytes, mast cells, tissue macrophages, and stem cells.

What is the principal cell type of connective tissue and what is its main function?

Fibroblast; responsible for synthesizing extracellular matrix fibers (collagen, elastic, reticular fibers) and ground substance.

Which hormone is produced exclusively by adipocytes to reduce appetite?

Leptin.

Which hormone stimulates the uptake and synthesis of triglycerides in adipocytes?

Insulin.

What volume of blood is typically present in an adult human?

$\sim 5\text{--}6\,\text{liters}$ of blood.

Which white blood cells are unique in their ability to return to the vascular compartment from interstitial compartments?

Lymphocytes.

At what exact standard pH level is blood acid-base balance maintained?

$\text{pH } 7.4$.

What percentage of total blood volume is occupied by cells versus plasma?

Cells occupy $\sim 45\%$ and plasma occupies $\sim 55\%$.

What is hematocrit and what are its normal percentage ranges in human males and females?

Hematocrit is the volume of packed erythrocytes in a blood sample; normal range is $\sim 39\text{--}50\%$ in males and $\sim 35\text{--}45\%$ in females.

What percentage of blood volume is comprised of leukocytes and platelets (the buffy coat)?

$\sim 1\%$ of blood volume.

What is the term for blood plasma that lacks coagulation or clotting factors?

Serum.

What is the most abundant protein found in blood plasma?

Albumin.

What are the percentages by weight of water, proteins, and other solutes in whole blood plasma?

$92\%$ water, $7\%$ proteins, and $1\%$ other solutes.

What are the percentage breakdowns of the main proteins in blood plasma?

Albumins $58\%$, Globulins $37\%$, Fibrinogen $4\%$, and Regulatory proteins $1\%$.

What are the normal concentration ranges per cubic millimeter ($\text{mm}^3$) for erythrocytes, platelets, and leukocytes?

Erythrocytes: $4.2\text{--}6.2\text{ million}/\text{mm}^3$; Platelets: $120\text{--}300\text{ thousand}/\text{mm}^3$; Leukocytes: $5\text{--}10\text{ thousand}/\text{mm}^3$.

What are the relative percentage ranges of the five white blood cell types in blood?

Neutrophils $60\text{--}70\%$, Lymphocytes $20\text{--}25\%$, Monocytes $3\text{--}8\%$, Eosinophils $2\text{--}4\%$, and Basophils $0.5\text{--}1\%$.

What main fiber type constitutes the matrix of cartilage tissue?

Collagen II fibers.

What are three unique vascular and neural features of cartilage matrix compared to other connective tissues?

Cartilage is avascular, has no nerves, and has no lymphatics.

What are the three distinct structural types of cartilage?

Hyaline cartilage, Elastic cartilage, and Fibrocartilage.

Where are hyaline, elastic, and fibrocartilage located in the human body?

Hyaline: nasal septum, joint surfaces, ribs; Elastic: external ear, larynx; Fibrocartilage: intervertebral disks, tendon/ligament attachments.

What proportion of bone matrix consists of inorganic calcium phosphate complexes?

$50\%$ of the matrix.

What are osteoblasts and what is their functional role?

Immature bone cells that synthesize and secrete osteoid (which mineralizes into bone) and do not divide.

What are osteoclasts and what is their lineage?

Large multinucleated macrophages derived from the monocyte lineage that remodel bone by resorbing bone matrix.

What are the two structural types of mature bone tissue?

Cancellous (spongy) bone and compact bone.

What structural repeating units compose compact bone tissue?

Haversian systems (osteons).

From which embryonic germ layer are all muscle tissues derived?

Mesoderm.

What specialized terms refer to the cell membrane, cytoplasm, and modified endoplasmic reticulum in muscle cells?

Sarcolemma (cell membrane), sarcoplasm (cytoplasm), and sarcoplasmic reticulum (modified ER).

Contraction in all muscle tissues depends on interactions between which two contractile proteins?

Actin and myosin.

Which cellular ion regulates muscle contraction across all muscle tissue types?

Calcium ($\text{Ca}^{++}$).

How are skeletal, cardiac, and smooth muscle classified structurally and functionally?

Skeletal: striated and voluntary; Cardiac: striated and involuntary; Smooth: non-striated and involuntary.

What layer of dense connective tissue surrounds an entire muscle unit?

Epimysium.

What connective tissue layer surrounds distinct bundles (fascicles) of muscle fibers?

Perimysium.

What delicate connective tissue layer surrounds each individual muscle fiber?

Endomysium.

What is a sarcomere?

The smallest repetitive subunit of the contractile unit in striated muscle, extending from Z-line to Z-line.

What are the cell length and diameter dimensions of skeletal muscle fibers?

Length up to $\sim 30\,\text{cm}$; diameter ranges from $10\text{--}100\,\mu\text{m}$.

In which functional category of muscle tissue are neuromuscular junctions exclusively found?

Voluntary (skeletal) muscle.

What neurotransmitter is packaged inside synaptic vesicles at neuromuscular junctions?

Acetylcholine (ACh).

What are the diameter, length, and nuclear features of cardiac muscle cells?

Diameter of $15\,\mu\text{m}$, length of $85\text{--}100\,\mu\text{m}$, possessing 1 or 2 centrally located nuclei.

Which connective tissue sheaths surrounding skeletal muscle fibers are absent in cardiac muscle tissue?

Perimysium and epimysium.

What distinct transverse lines join individual cardiac muscle cells end-to-end?

Intercalated disks.

Through which specialized junctions within intercalated disks is cardiac contraction passed cell to cell?

Gap junctions.

What is the characteristic cell shape of smooth muscle tissue?

Elongated, nonstriated, fusiform cells.

What structural sites in smooth muscle contain $\alpha\text{-actinin}$ for filament attachment and propagation of contraction?

Dense bodies ( cytoplasmic densities).

Which intermediate filament proteins are present in smooth muscle cells?

Desmin and vimentin.

What are the two major anatomical divisions of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS).

How many neurons and interconnections are estimated to be present in the nervous system?

More than $100\text{ million}$ neurons that make at least $1,000$ interconnections each.

What are the functional differences between afferent and efferent neurons?

Afferent neurons receive and transmit sensory inputs from the environment to the CNS; efferent neurons transmit motor outputs generated in the CNS to the periphery.

What three divisions make up the autonomic nervous system?

Parasympathetic division (rest and digest), sympathetic division (fight or flight), and enteric division (controls GI function).

What are the dark-staining chromatophilic substances found inside neuron cell bodies?

Nissl bodies.

What are the three connective tissue layers surrounding nerve fibers in a peripheral nerve, from outermost to innermost?

Epineurium, perineurium, and endoneurium.

What four organ components comprise the human urinary system?

Kidney, ureter, bladder, and urethra.