Solutions, Diffusion & Osmosis

• Solutions are fluids containing dissolved particles, solvents are the fluids themselves, and solutes are the dissolved particles.
• Diffusion is a passive process where particles move from high to low concentration areas.
• Osmosis is the diffusion of water through a selectively permeable membrane, limiting the diffusion of solute particles.
• A hypertonic solution has a higher solute concentration, isotonic solutions have equal solute concentrations, and hypotonic solutions have a lower solute concentration.
• Cells in hypotonic solutions can swell and burst due to water influx, while those in hypertonic solutions can shrink and die due to water efflux.
• Facilitated diffusion uses membrane proteins (transporters) to move large or charged materials.

Types of Facilitated Diffusion

• Channel-mediated passive transport allows only one type of solute to pass through protein tunnels.
• Carrier-mediated passive transport involves membrane proteins that bind to the solute, change shape, and release the solute on the other side.
• Protein pumps utilize ATP to move molecules in or out of the cell.
• Endocytosis involves the plasma membrane trapping extracellular material and bringing it into the cell in a vesicle.

Types of Endocytosis

• Receptor-mediated endocytosis uses surface receptors to attach to substances and trigger endocytosis.
• Phagocytosis is the process of solids being taken into the cell, also known as "cell eating".
• Pinocytosis is the process of taking in fluids, also known as "cell drinking".
• Exocytosis involves large molecules enclosed in vesicles being transported to the plasma membrane for release.
• Simple diffusion, osmosis, and facilitated diffusion are passive transport mechanisms.
• Passive transport moves material from high to low concentration.
• Sodium-potassium pumps, endocytosis, and exocytosis, and calcium pumps are active transport mechanisms
• Active transport moves material from low to high concentration.
• Catalysts speed up reactions.
• Enzymes are biological catalysts that reduce the activation energy needed for a reaction
• Activation energy is the energy required to start a reaction.
• Enzymes reduce the energy required to start a reaction
• Enzymes are usually made of proteins
• The active site on an enzyme is where the substrate (reactant) molecule fits.
• Enzymes can be reused after a chemical reaction.
• Allosteric effectors affect enzyme action by changing the enzyme's shape; temperature, pH, radiation, cofactors, and metabolic end products can be allosteric effectors.
• Feedback inhibition utilizes cofactors as an OFF switch.
• Enzymes can speed up a chemical reaction in both directions.
• Cellular respiration is the breakdown of glucose to make ATP.
• Anaerobic respiration occurs without oxygen, while aerobic requires oxygen.

Stages of Cellular Respiration

• Glycolysis occurs in the cytoplasm and breaks down glucose.
• The citric acid cycle occurs in the mitochondria and breaks C-C bonds to create NADH & FADH2 (electron carriers).
• The electron transport system occurs if oxygen is present to produce ATP.
• Glycolysis results in: Glucose + 2 ATP -> 4 ATP + 2 NADH + 2 Pyruvate.
• The citric acid cycle results in 2 Pyruvic acid → 2 NADH + 2 Acetyl-CoA, and 2 Acetyl-CoA → 2ATP + 6 NADH + 2 FADH2, with CO2 released.
• As electrons are transported along the electron transport chain, energy is used to pump protons (H+) to the intermembrane space.
• A gene is a DNA segment with nucleotide pairs that contains a code for synthesizing one RNA molecule, which translates into a polypeptide.
• Transcription is the process where RNA forms along a segment of one strand of DNA.
• mRNA is a copy of the code for one polypeptide (protein), made through transcription via RNA polymerase.

RNA Components

• Introns are non-coding sections of a DNA or RNA molecule.
• Exons are coding sections of the RNA transcript that get translated into a protein.
• Translation uses mRNA to make a protein (occurs in the cytoplasm).
• A codon is a set of 3 nitrogen bases (nucleotides) read as a certain code on mRNA.
• rRNA is ribosomal and part of the ribosomes.
• tRNA transfers amino acids to a specific mRNA codon at the ribosome during translation.
• Translation happens at the ribosome.
• AUG is the start codon.

Interphase Stages

• G1: normal growth.
• S: DNA synthesis.
• G2: growth.
• Telomeres are noncoding DNA segments at chromosome ends.
• Mitosis is the division of the nucleus to form identical copies.

Mitosis Phases

• Prophase: nucleus disappears; chromatin forms chromosomes; centrioles attach to chromosomes.
• Metaphase: chromosomes move to the middle.
• Anaphase: chromatids are pulled apart, and cytokinesis begins.
• Telophase: chromatids are pulled to each part of the cell; the cell starts to pinch apart and complete cytokinesis to separate the new cells.
• Cytokinesis is the division of cytoplasm, occurring in anaphase and telophase.
• Meiosis occurs only in sexual organs (tests, ovaries), resulting in cells with half the genetic content and unique genetic material.
• A tissue is a group of cells with a common function.
• The four developed tissue types are epithelial, connective, muscle, and nervous tissue.
• Connective tissue is the most abundant/widespread tissue type.
• The three nonspecialized tissue types in the embryo are endoderm, mesoderm, and ectoderm.
• The extracellular matrix is a nonliving fluid material between cells that supports tissues and facilitates communication.

Matrix Protein Fibers

• Collagen gives strength and durability.
• Elastin provides stretchiness.
• Regenerated tissue involves phagocytic cells removing dead or injured cells filled in with new epithelial and connective tissues.
• Scar tissue is connective tissue instead of muscle/nervous tissue.
• Epithelial and connective tissues have the greatest ability to regenerate.
• A neoplasm is any abnormal cell growth.
• Benign neoplasms are slow-growing with little spreading.
• Malignant are fast-growing, likely to spread and are therefore cancerous .
• Neoplasms of epithelial tissue are called "carcinoma"- ex. Malignant melanoma (aggressive skin cancer)
• Neoplasms of connective tissue are called "sarcoma"- ex. Lymphoma (blood cancer)

Cancer Factors

• Factors include genetic factors, carcinogens, age, and metabolic factors.
• Methods of detection include self-examination, medical imaging, blood tests, and biopsy.
• Common therapies include chemotherapy, radiation therapy, laser therapy, and immunotherapy.
• Epithelial tissue functions include protection, sensory functions, secretion, absorption, and excretion.
• Membranous and glandular are the two basic types of epithelial tissue.
• Membranous is flat sheets
• Glandular tissue makes chemicals and secrete (release)
• A basement membrane is connective tissue under the membrane.
• Epithelial tissue is typically avascular (no direct blood supply).

Epithelial Tissue Categories by Shape

• Squamous: flat cells
• Cuboidal:: squared/cubed
• Columnar: taller than they are wide
• Pseudostratified columnar: all tall but look weird and irregular shape
• Simple: single layer.
• Stratified: many layers.

Types of Membranous Epithelial Tissue

• Simple squamous epithelium: for absorption or secretion; one layer of flat cells; alveoli in the lungs- sac where gas exchange occurs.
• Simple cuboidal epithelium: in glands and ducts; one cell layer of cube shaped cells.
• Simple columnar epithelium: in digestive system; single layer of tall, column shaped cells; often modified for specialized functions (goblet cells – mucus secreting, cilia – movement, microvilli – absorption).
• Simple pseudostratified columnar: airways; motile cilia and mucus are important.
• Stratified cuboidal epithelium: two or more rows of cells; basement membrane is indistinct; located in sweat gland ducts and pharynx.
• Stratified columnar epithelium: rare- located in segments of male urethra and near anus.
• Nonkeratinized Stratified squamous epithelium: lines the vagina, mouth, and esophagus; free surface is moist; primary function is protection.
• Keratinized Stratified squamous epithelium: multiple layers of flat,squamous cells; cells filled with keratin; covers outer skin on body surface.
• Transitional epithelium: changes shape when stretched; urinary bladder-hold urine.

Epithelial Tissue Components

• A goblet cell (AKA mucous gland) is a mucus-secreting cell; found in simple columnar epithelium and pseudostratified columnar.
• Keratin is a protein that provides extra protection and waterproofing.

Glandular Epithelium

• Exocrine glands discharge secretions into ducts; secrete through ducts to surface.
• Endocrine glands are "ductless" glands make hormones; secrete without ducts to surrounding fluids.

Exocrine Gland Types

• Apocrine - small pieces of cell leaves with chemicals (milk and puberty sweat).
• Holocrine - whole cells leave with chemicals (oil glands).
• Merocrine- no cell destruction; chemicals leak out (saliva, normal sweat).
• Connective tissue functions: connects, supports, transports, protects.

Major Connective Tissue Categories

• Fibrous: loose fibrous (areolar), adipose, reticular, dense irregular, and dense regular (collagenous and elastic).
• Bone: compact and cancellous (spongy).
• Cartilage: hyaline, fibrocartilage, and elastic.
• Blood
• Loose fibrous (areolar): fibroblasts and macrophages; located between tissues and organs to bind them together.
• Adipose: adipocytes; food reserve, support, protection, heat generation, and insulation; produces leptin, which signals the brain concerning how much fat is stored.
• Reticular: fibrous tissue that forms the framework for the spleen, lymph nodes and bone marrow- immune system.
• Dense irregular: fibers intertwined irregularly to form a thick mat.
• Dense regular: bundles of fibers are arranged in regular parallel rows.
• Collagenous dense regular fibrous CT: tendons (muscle to bone) and ligaments (bone to bone)

Fibrous Connective Tissue

• Fibroblasts are cells that make fibers in CT.
• Adipocytes are fat cells in fibrous connective tissue.
• Brown fat is used to produce heat found in infants to help contribute to heat as they develop muscles
• Osteocytes is a major cell type in bone (osseous) tissue.

Bone Functions

• Support-Attaches to organs
• Protection-Surrounds organs
• Point of attachment for muscles
• Reservoir for minerals: calcium and phosphate
• Support blood-forming tissue: red bone marrow creates blood cells
• Osteon (haversian system) is the structural unit.

Osteon Features

• Central canal: blood vessel in the middle
• Lamellae: rings around the central canal
• Lacuna: holes containing osteocytes
• Canaliculi: cracks between lacuna and the central canal
• Cancellous (spongy) bone has lacuna (holes) and osteocytes (cells).
• Trabeculae are thin beams of bone.
• It has a sponge like appearance contains red bone marrow.
• Spongy bone contains red bone marrow that forms blood cells.
• Chondrocytes is the cell type, and cartilage is avascular.
• Perichondrium is the membrane that surrounds cartilage.

Cartilage Types

• Hyaline: most common type; in nose and end of bones.
• Fibrocartilage: strongest; shock absorption; lots of fibers; intervertebral disks (backbone) and pubic symphysis (holds public bones together).
• Elastic: lots of elastin (stretchy); found in external ear and voice box.
• Hyaline cartilage is the most abundant.
• Fibrocartilage is the strongest.
• Blood is only liquid tissue with no fibers.
• Blood plasma liquid fraction (of blood (the matrix). Makes up 55% of total blood volume.

Formed Blood Elements

• Red blood cells (erythrocytes)
• White blood cells (leukocytes)
• Platelets (thrombocytes)

Blood Functions

• Transportation
• Regulation of body temperature
• Regulation of body pH
• White blood cells destroy bacteria
• Skeletal: striated voluntary muscle tissue; bone; multiple nuclei.
• Smooth: nonstriated; involuntary; muscle tissue; digestive tract; one nucleus.
• Cardiac: striated involuntary muscle tissue; heart; one nucleus.
• The muscles are used for movement and heat production.
• Intercalated disks are gap junctions that help conduct electricity from one cell to the next.
• Nervous tissue has the ability to make electric impulses
• Conductivity Ability to carry electric impulses

Nervous Tissue Organs

• Brain: processing center
• Spinal cord: relay station
• Nerves: wires that move electricity around
• A neuron is a conducting unit of the system.
• Dendrite (one or more): receives info.
• Cell body,or soma: contains nucleus.
• Axon (single process): carries electricity, ends in axon terminals/synaptic knobs, which sends signal to target.
• Neuroglia (glial cell): Special connecting, supporting,, and coordinating cells that surround neurons.
• The skin is the largest organ.
• The skin also known as Integument and cutaneous membrane.
• The two layers of the skin: Epidermis: superficial, keratinized stratified squamous epithelium, Dermis: deep and thicker , Hypodermis: below the skin.

Types of Skin

• Thin: has hair and a smooth surface; most common
• Thick: has no hair and a ridged surface; thicker epidermis
• Thick skin founded Mainly Palms, fingertips, soles of feet.

Skin Cells

• Keratinocytes: make keratin (protein in skin cells which protects them from drying out) in skin and hair and nails.
• Melanocytes: make melanin (pigment gives skin/hair color).
• Dendritic cells: play a role in immune response- protection from invaders.
• Tactile epithelial cells (merkel cells): receptors for light touch.
• Lamellar corpuscles for deep pressure.

Epidermis Layers Top to Bottom

• Stratum corneum: dead cells (gets shed).
• Stratum lucidum: only in thick skin.
• Stratum granulosum: makes keratin.
• Stratum spinosum: cells start to stretch and connect to each other to make a network of cells.
• Stratum basale: divides to produces new cells.
• Stratum lucideum is not found on thin skin.
• The function of the dermis is gives strength to the skin- anchors skin to body.
• Serves as a reservoir storage area for water and electrolytes.
• The layers of the dermis: Papillary layer: thin bumps called papillae, loose fibrous CT and Reticular layer: dense irregular CT with lots of collagen and some elastin.
• Papillary layer is more Superficial
• Arrector pili muscles is in the dermis that attached to hair Makes hair stand erect- “goosebumps”; involuntary.
• The hypodermis is also called subcutaneous layer or superficial fascia that is not part of the skin.
• Melanin main pigment in skin made by melanocytes.
• Eumelanin dark brown and Pheomelanin reddish-orange.
• Melanocytes produce melanin.
• Albinism is a mutation that stops melanin production.
• Factors that affect melanin production ,Radiation exposure increases production, Heredity (DNA).
• Melanin functions Forms protective cap on nucleus of keratinocytes to protect them from UV light.
• Beta carotene orange pigment, Hemoglobin red pigment and Cyanosis blue pigment.
• Cyanosis an oxygen poor blood.
• Shedding of epithelial elements called desquamation
• Antibacterial,, lubrication,, hydration of skin,, buffer, blockage
• Skin functions are protection physical barrier from outside, Vitamin D production, helps absorb calcium, Sensation senses touch (tactile corpuscles), pressure (lamellar corpuscles), temperature, and pain, Flexibility: prevents tearing, Excretion releases chemicals (oil, sweat), Immunity- dendritic cells, Body temperature homeostasis:

Body functions

• Hypothalamus (control center) is used to regulates body temperature.
• Evaporation and Blood flow helps body get rid of Heat
• Lanugo hair Before birth
• Vellus : After brith on most of body
• Terminal: after birth; axilla, pubic hair, beard hair
• The hair follicle Structure that hair grows from
• Hair Parts, Papilla: blood supply, Germinal matrix; form hair.
• Root where hair grows and shaft outside of skin.
• The Medulla is the middle part of the hair.
• The Cortex is outside of the hair.
• Results from a combination of genetic tendency and male sex hormones (tendency to become bald)
• Melanin makes hair have different colors; white hair is from melanocytes not working as much.
• Major Protein Hair And Nails Made Of, Keratin