Human Biology Overview

Peripheral Resistance Regulation

• Arterioles are the primary site for regulating peripheral resistance.

Excitation-Contraction Coupling

• Action potential (AP) along the T-tubule triggers the release of calcium ions (Ca²⁺) from the sarcoplasmic reticulum (SR) near myofibrils.
• This calcium release initiates muscle contraction.

Atrioventricular Valves

• The mitral valve and tricuspid valve are the atrioventricular valves.

Cardiac Output

• Cardiac output is calculated by multiplying heart rate by stroke volume.

Germ Layers

Ectoderm

• Outermost germ layer.
• Develops into skin and the nervous system.

Mesoderm

• Middle germ layer.
• Forms muscle, skeleton, and organs related to circulation, reproduction, and excretion.

Endoderm

• Innermost germ layer.
• Develops into the lining of the gut and associated organs.

Types of Tissues

• Epithelial tissue: Lines body surfaces.
• Muscle tissue: Composed of fibers that contract.
• Nervous tissue: Composed of cells with projections for transmitting electrical signals.
• Connective tissue: Diverse group including loose connective tissue, cartilage, bone, and blood.

Basic Cell Structure

• Nucleus, cytoplasm, and cell membrane are the components of a basic cell structure.

Nucleus

• Organelle containing chromosomes.

Cytoplasm

• Jelly-like substance within the cell, suspending organelles.

Nucleobases in DNA

• Adenine (A)
• Thymine (T)
• Guanine (G)
• Cytosine (C)

Chromosome

• A structured package of DNA.

Cell Cycle Phases

• Interphase:
  • G1: Cell growth.
  • S: DNA synthesis.
  • G2: Growth and preparation for mitosis.
• Mitosis: Cell division.

Mitosis Phases

• Prophase: Chromatin condenses into chromosomes.
• Metaphase: Spindle fibers attach, chromosomes align at the cell's center.
• Anaphase: Sister chromatids separate and move to opposite poles.
• Telophase & Cytokinesis: Two daughter cells form.

Regulator Molecules

• Molecules that either promote or halt the cell cycle.

Cancer

• Characterized by uncontrolled cell growth.

Proto-oncogenes

• Precursors to oncogenes.
• Code for positive cell cycle regulators.

Meiosis

• Cell division in germ cells producing gametes (sperm or egg).
• Results in four daughter cells each with half the chromosomes of the parent cell.

Zygosity

• Degree of similarity of alleles for a trait in an organism.

Homozygous/Heterozygous

• Homozygous: Two copies of the same allele.
• Heterozygous: One dominant and one recessive allele.

Allele

• Alternative form of a gene (e.g., A, B, and O blood types).

Autosomal Dominant/Recessive

• Dominant: Only one affected allele needed for expression.
• Recessive: Two affected alleles needed for expression; one affected allele is a carrier.

Central Dogma of Molecular Biology

• DNA → RNA → Protein. Genetic information flows in one direction.

Translation

• mRNA decoding to synthesize protein.

Transcription

• DNA to RNA process.

Protein Folding

• Amino acid chain folding to a functional protein.

Peptide Bond

• Chemical bond linking amino acids.

Peptide

• Chain of amino acids.

Ribosome

• Organelle synthesizing protein.

Gene

• Functional unit of DNA.

Codon

• Three-base sequence in DNA or RNA specifying an amino acid.

Protein Structures

• Primary: Amino acid sequence.
• Secondary: Local folding (alpha-helices, beta-sheets).
• Tertiary: 3D folding pattern due to interactions.
• Quaternary: Protein with multiple polypeptide chains.

Organelles

• Structures within a cell performing specific functions.

Cytosol

• Fluid component of the cytoplasm.

Endoplasmic Reticulum

• Network of membranes involved in protein and lipid transport.

Golgi Apparatus

• Modifies, sorts, and packages proteins and lipids.

Endocytosis

• Cell taking material into the cell via membrane infolding.

Exocytosis

• Cell releasing material outside the cell.

Lysosomes

• Organelles containing enzymes for cellular waste breakdown.

Mitochondria

• Site of ATP (energy) production. Contains DNA.

ATP

• Adenosine triphosphate, the main energy currency of cells.

ATP Production

• Anaerobic: No oxygen, small ATP yield, in cytoplasm.
• Aerobic: Requires oxygen, large ATP yield, in mitochondria.

Cell Membrane Structure

• Double lipid layer with polar and nonpolar ends.

Diffusion

• Movement of solutes from high to low concentration.

Osmosis

• Solvent movement from low solute concentration to high solute concentration across a membrane.

Filtration

• Movement across a membrane (sieve-like) due to pressure difference.

Active Transport

• Energy-requiring movement of material against a concentration gradient.

Sodium-Potassium Pump

• Active transport using energy to move Na+ out and K+ into the cell.

Resting Membrane Potential

• Electrical charge of a neuron at rest (-70mV).

Depolarization

• Inside of the cell becomes less negative (Na+ influx).

Action Potential

• Rapid change in membrane potential during signaling.

Threshold Potential

• Membrane potential value needed to initiate an action potential.

Repolarization

• Return of the membrane potential to resting state (K+ efflux).

Central Nervous System

• Brain and spinal cord.

Peripheral Nervous System

• Nerves connecting the CNS to the rest of the body (sensory & motor).

Neuron

• Nerve cell, primary function: signal conduction.

Nuclei

• Clusters of neuron cell bodies in the CNS.

Ganglia

• Clusters of neuron cell bodies in the PNS.

Glial Cells

• Supporting cells in the nervous system.

Myelin Sheath

• Fatty insulation around neurons, speeds signal conduction.

Multiple Sclerosis

• Myelin sheath destruction, impacting signal transmission.

Synapses

• Junctions where neurons communicate.

Neurotransmitters

• Chemical messengers transmitting signals between neurons.

Peripheral Nervous System Divisions

• Sensory division: Input from receptors.
• Motor division: Output to muscles/glands.
  • Somatic nervous system: Voluntary control.
  • Autonomic nervous system: Involuntary control.

Peripheral Nerves

• Most nerves are both sensory and motor. Sensory nerves carry input.

Dorsal Root

• Sensory input to the spinal cord.

Ventral Root

• Motor output from the spinal cord.

Proprioceptors

• Receptors in muscles/tendons/joints monitoring position and movement.

Static/Dynamic Equilibrium

• Static: Body position.
• Dynamic: Body movement/acceleration.

Sight

• Light passes through the lens and projects onto the retina. Focal point determines vision clarity.

Myopia

• Nearsightedness. Focal point in front of the retina. Fixed with concave lens.

Hypermetropia (Hyperopia)

• Farsightedness. Focal point behind the retina. Fixed with convex lens.

Retina

• Light-sensitive layer at the back of the eye containing photoreceptor cells.

Motor Nerve Cells

• Conduct impulses from the brain to muscles/glands.

Motor Unit

• Motor neuron and all muscle fibers it innervates.

Neuromuscular Junction

• Synapse between motor neuron and muscle fiber.

Skeletal Muscle Stimulation

• Short action potential triggers a short twitch. Maximal power with no relaxation between pulses.

Antagonistic Action

• Opposing muscle action.

Sympathetic/Parasympathetic Nervous Systems

• Sympathetic: "Fight or flight," increases activity, spinal cord centers.
• Parasympathetic: "Rest and digest," decreases activity, brain stem and spinal cord centers.

Cerebrospinal Fluid

• Fluid cushioning and protecting the CNS.

Spinal Cord Functions

• Conduction, signal processing, and reflexes.

Tendon/Stretch Reflex

• Sensory signal to spinal cord synapses with motor neuron.

Crossed Extensor Reflex

• When one leg withdraws, the opposite leg extends.

Cerebrum

• Area of the brain responsible for voluntary movement, sensory perception, thinking, etc.

Cortex

• Outermost layer of the brain, responsible for higher-level functions.

Frontal Lobe

• Rational behavior, motor control.

Parietal Lobe

• Sensory information, language processing.

Occipital Lobe

• Visual processing.

Temporal Lobe

• Memory and learning related functions.

Primary Motor Area

• Plans and executes voluntary movement.

Thalamus

• Relay center for sensory information.

Basal Ganglia

• Regulates voluntary movement, procedural learning, and habits.

Parkinson's Disease

• Degeneration of dopamine-releasing neurons in the basal ganglia, causing tremors, rigidity, etc.

Cerebellum

• Coordinates movement, posture, and balance.

Limbic System

• Involved in emotions, motivation, and memory.

Amygdala

• Processes emotions, particularly fear and aggression.

"Happy Chemicals"

• Serotonin: Significance, importance.
• Dopamine: Gratification, satisfaction.
• Oxytocin: Social bonding.
• Endorphins: Pain relief.

Hippocampus

• Processes memories into long-term storage; crucial for learning.

Referred Pain

• Pain felt in a location other than where the pain originates.

This quiz covers essential concepts in human biology, including the regulation of peripheral resistance, excitation-contraction coupling, and the roles of different germ layers. It also addresses the structure and function of atrioventricular valves and the calculation of cardiac output, along with the types of tissues in the body.