NCLEX REVIEW

Types and Functions of Muscle Tissues in the Human Body

Cardiac Muscle Tissue

• Located in the heart

• Involuntary muscle type responsible for pumping blood throughout the body

Smooth Muscle Tissue

• Found in the walls of hollow organs like the intestines, blood vessels, and bladder

• Involuntary muscle type involved in various functions such as peristalsis and vasoconstriction

Skeletal Muscle Tissue

• Attached to bones by tendons

• Voluntary muscle type responsible for movement and locomotion

Mechanism of Skeletal Muscle Function

Voluntary Motion

• Skeletal muscles contract in response to signals from the nervous system

• Muscle fibers contain sarcomeres that shorten during contraction

Regulation of Body Temperature

• Muscle contractions generate heat through cellular respiration

• Help in maintaining normal body temperature

Structure and Activation of Muscle Fibers

Components of a Muscle Fiber

• Sarcolemma (cell membrane of muscle fiber)

• Sarcoplasm (cytoplasm of muscle fiber)

• Myofibrils (contractile proteins within muscle fiber)

Activation of Skeletal Muscles

• Requires a signal from the nervous system in the form of a motor neuron impulse

• Release of calcium ions triggers muscle contraction

Functions of Cardiac and Smooth Muscles

Cardiac Muscle

• Exclusive role in the heart for pumping blood

• Involuntary contractions ensure continuous heart function

Smooth Muscle

• Regulating blood flow in blood vessels

• Assisting in peristalsis for digestion

• Controlling bladder function

• Regulating pupil size in the eye

• Constricting or dilating airways in the lungs

Passive Transport

Diffusion

• The movement of molecules in a fluid or gas from a region of higher concentration to a region of lower concentration.

• Concentration Gradient: The difference in the concentration of a substance from one location to another.

• Molecules diffuse down their concentration gradient- from higher concentration to lower concentration.

• They spread out.

Osmosis

• The process of water molecules moving across a semipermeable or selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

• Semipermeable/Selectively Permeable: Condition or quality of allowing some, but not all, material to cross a barrier or membrane.

• Water moves into a cell when the solution surrounding the cell is hypotonic.

• Water moves out of a cell when the solution surrounding the cell is hypertonic.

Isotonic

• A solution has the same amount of dissolved particles as the cell.

• Water molecules move in and out of the cell at the same rate.

Hypotonic

• Lower concentration of dissolved particles than the cell.

• Water molecules are concentrated outside the cell.

• High solutes inside the cell causing water to rush in toward the solutes.

• If too much water enters the cell, the cell could burst.

Hypertonic

• Solution has a higher concentration of dissolved particles than a cell.

• The collapse of a walled cell's cytoplasm due to a lack of water.

• Water concentration is higher inside the cell than the outside.

• Solutes are higher outside the cell causing water to rush out of the cell.

Facilitated Diffusion

Facilitated Diffusion

• The diffusion of molecules across a membrane through transport proteins.

• Membrane proteins 'help' or facilitate the process of polar or ions (charged particles) moving across the membrane through a protein tunnel.

• The movement of molecules down a concentration gradient through transport proteins in the cell membrane is a type of facilitated diffusion.

Active Transport

Active Transport

• Proteins can transport materials against a concentration gradient.

• The proteins are often called pumps.

• Active transport requires energy from the cell.

• This process uses transport proteins powered by chemical energy, ATP.

• Drives molecules across a membrane from a region of lower concentration to a region of higher concentration.

• Transport proteins span the membrane and change shape when they bind to a target molecule or molecules.

• Some proteins bind very specifically to only one type of molecule.

Endocytosis

• The movement of large amounts of a substance or a large molecule.

• The cell engulfs the substance or molecule, surrounding it with a membrane.

• The vesicle forms and merges with a lysosome to be broken down into usable parts.

• Phagocytosis: Engulfing large particles 'cell eating'.

Exocytosis

• The release of substances by a cell through the fusion of a vesicle with the cell membrane.

• Vesicle forms around material to be removed or secreted.

• Vesicle is transported to the cell membrane.

• Vesicle membrane fuses with the cell membrane and releases its contents.

Definition of Biology

• Biology is the study of living things.

Scientific Method

• The scientific method consists of the following steps: observation, hypothesis, experiment, results, conclusion, compare and publish.

Hypothesis and Theory

• A hypothesis is an educated guess.

• A theory is an explanation based on repeated hypotheses and experiments.

Control and Experiment

• A control is something that is not treated.

• An experiment is the testing of a theory.

Data and Replicate

• Data refers to the results collected from experiments.

• To replicate means to complete the experiment again.

Blind Testing and Double Blind

• Blind testing is when the investigator is unaware of the nature of the treatment.

• Double blind is when both the investigator and participant are unaware of the nature of the treatment.

Anatomy

Definition and Scope

• The study of the form or structure of living things.

• Examines the relationships between different body parts and their functions.

Body Cavities

• Abdominopelvic cavity: the continuous internal opening that includes both the abdominal and pelvic cavities. It houses organs such as the reproductive and excretory organs.Abdominal Cavity: Space bounded by the abdominal walls, diaphragm, and pelvis. Contains organs such as the stomach, liver, and intestines.

• Cranial cavity: Opening inside the skull that holds the brain. Provides protection and support for the brain.

• Middle ear cavities: Openings in the skull that serve as chambers for transmitting and amplifying sound. Connected to the nasal cavity and throat.

• Nasal cavity: Opening within the nose. Lined with mucous membranes and helps filter, warm, and moisten the air we breathe.

• Oral cavity: Opening within the mouth. Contains the tongue, teeth, and salivary glands. Involved in the process of digestion and speech production.

• Orbital cavities: Openings that hold the eyes. Provide protection and support for the eyes and contain structures such as the eyeballs and associated muscles.

• Pelvic cavity: Internal opening that holds the reproductive and excretory organs. Located within the pelvic region of the body.

• Spinal cavity: Internal opening that houses the spinal cord. Provides protection and support for the spinal cord, which transmits nerve signals.

• Thoracic cavity: Internal opening that houses the heart and lungs. Located within the chest region of the body and protected by the ribcage.

Body Planes

• Frontal plane: Invisible vertical flat surface that divides the body into front and back halves. Used as a reference for describing the position of body structures.

• Sagittal plane: Invisible vertical flat surface that divides the body into right and left halves. Used as a reference for describing the position of body structures.

• Transverse plane: Invisible horizontal flat surface that divides the body into top and bottom halves. Used as a reference for describing the position of body structures.

Physiology

Definition and Scope

• The study of how living things function or work.

• Focuses on the processes and mechanisms that allow organisms to maintain homeostasis and carry out their various functions.

Homeostasis

• The state of regulated physiological balance within an organism.

• Involves maintaining stable internal conditions despite external changes and is essential for survival.

Homeostatic Mechanisms

• Processes that maintain homeostasis in the body.

• Involve feedback loops and adjustments to ensure the body's internal conditions remain stable.

Metabolism

• All the chemical reactions that occur within an organism to maintain life.

• Involves processes such as digestion, respiration, and energy production.

Organ Systems

• Groups of two or more organs working together to perform specific functions.

• Examples include the respiratory system, digestive system, and circulatory system.

Cells and Tissues

• Cells: Smallest living building blocks of all organisms. Responsible for carrying out essential functions and make up tissues, organs, and organ systems.

• Tissues: Organized groups of similar cells that work together to perform a specific function. Form the structural basis of organs and contribute to their overall function.

Movement Terminology

Abduction and Adduction

• Abduction: Movement of a body segment away from the body in the frontal plane.

• Adduction: Movement of a body segment closer to the body in the frontal plane.

Flexion and Extension

• Flexion: Forward movement of a body segment away from anatomical position in the sagittal plane.

• Extension: Movement that returns a body segment to anatomical position in the sagittal plane.

Rotation

• Lateral rotation: Outward (lateral) movement of a body segment in the transverse plane.

• Medial rotation: Inward (medial) movement of a body segment in the transverse plane.

Other Movements

• Circumduction: Rotational movement of a body segment such that the end of the segment traces a circle.

• Dorsiflexion: Movement of the top of the foot toward the lower leg.

• Eversion: Movement in which the sole of the foot is rolled inward.

• Hyperextension: Backward movement of a body segment past anatomical position in the sagittal plane.

• Plantar flexion: Downward motion of the foot away from the lower leg.

• Pronation: Medial rotation of the forearm (palm down).

• Supination: Lateral rotation of the forearm (palm up).

• Radial deviation: Rotation of the hand toward the thumb.

• Ulnar deviation: Rotation of the hand toward the little finger.

Chemistry Basics

Atoms and Molecules

• Atoms: Tiny particles of matter that are the building blocks of all substances. Combine to form molecules and play a fundamental role in chemical reactions within the body.

• Molecules: Combinations of two or more atoms bonded together. Building blocks of substances and play a crucial role in various biological processes.

Metabolic Rate

• The speed at which the body consumes energy.

• Influenced by factors such as age, gender, body composition, and physical activity level.

Homeostatic Imbalance

• The diminished ability of organ systems to keep the body's internal environment within normal ranges.

• Can lead to various health problems and diseases.

Endocrine System and Hormones

Overview of Hormones and Glands

• Hormones are chemicals released directly into the bloodstream by glands.

• These hormones cause specific effects in target organs.

• Adrenal glands and thyroid gland are two important glands in the endocrine system.

Adrenal Glands and Adrenaline

Function of Adrenal Glands

• Adrenal glands are located at the top of the kidneys.

• During fear or stress, adrenal glands produce adrenaline.

• Adrenaline is released into the blood and increases heart rate.

Effects of Adrenaline

• Increased heart rate delivers more oxygen and glucose to the brain and muscles.

• Oxygen and glucose are essential for aerobic respiration.

• Prepares the body for 'fight-or-flight' response.

Thyroid Gland and Thyroxine

Function of Thyroid Gland

• Thyroid gland is located in the base of the neck.

• It releases the hormone thyroxine.

• Thyroxine stimulates the body's basal metabolic rate.

Effects of Thyroxine

• Stimulates chemical reactions in the body to occur at a faster rate.

• Plays a crucial role in growth and development.

Control of Thyroxine Levels

• Thyroxine levels are controlled by negative feedback.

• When thyroxine levels fall, the pituitary gland releases TSH to trigger more thyroxine release.

• Increased thyroxine levels are detected by the brain, leading to a decrease in TSH release.

Negative Feedback Mechanism

General Idea Behind Negative Feedback

• Negative feedback is a regulatory mechanism in the body.

• Brain monitors thyroxine levels and regulates TSH release accordingly.

• Maintains a balance in thyroxine levels through a feedback cycle.

Examples of Negative Feedback Cycles

• Control of blood glucose and menstrual cycle involve negative feedback.

• These cycles help in maintaining homeostasis in the body.

Animal Cells

• Plasma Membrane: A phospholipid bilayer with embedded proteins that separates the inside of the cell from its environment.

• Cytoplasm: The contents of a cell between the plasma membrane and the nuclear envelope.

• Nucleus: Houses the cell’s DNA in the form of chromatin. Directs synthesis of ribosomes and proteins. Surrounded by the nuclear envelope.

• Endoplasmic Reticulum (ER): Series of interconnected tubules that modify proteins and synthesize lipids. Has 2 separate types.

• Golgi Apparatus: Flattened membranous sacs that sort, tag, package, and distribute lipids and proteins.

• Lysosomes: The cell’s “Garbage Disposal.” Digestive enzymes inside of lysosomes help break down proteins, polysaccharides, lipids, nucleic acids, and worn-out organelles. Also helps destroy diseases causing organisms in tandem with your immune system.

• Vacuoles: Membrane bound sacs used for storage and transportation. Vacuoles are larger and what we will talk most about. They do not fuse to membranes of other organelles while vesicles can.

• Mitochondria: The “powerhouse” or “Energy Factory” of the cell. Makes adenosine triphosphate (ATP), which is the main energy carrying molecule for cells. The formation of ATP by breaking down Glucose is called cellular respiration. Mitochondria have their own DNA and Ribosomes.

• Ribosomes: Responsible for protein synthesis. Appear as free floating dots in the cytoplasm, but attach to the Smooth ER, turning it into Rough ER when it’s time to make protein.

Organelles and Structures of Animal Cells

Plasma Membrane

• A phospholipid bilayer with embedded proteins that separates the inside of the cell from its environment.

Cytoplasm

• The contents of a cell between the plasma membrane and the nuclear envelope.

Nucleus

• Houses the cell’s DNA in the form of chromatin

• Directs synthesis of ribosomes and proteins

• Surrounded by the nuclear envelope

Endoplasmic Reticulum (ER)

• Rough ER: Ribosomes are attached to the cytoplasmic surface which give it a studded appearance. Responsible for synthesizing proteins while attached to the ER, folding or adding sugars to molecules, and making phospholipids for cell membranes.

• Smooth ER: Has few or no ribosomes attached to the surface. Responsible for the synthesis of carbohydrates, lipids (including phospholipids), and steroid hormones. Also involved in detoxification and storage of calcium ions.

Golgi Apparatus

• Flattened membranous sacs that sort, tag, package, and distribute lipids and proteins.

Lysosomes

• The cell’s “Garbage Disposal.” Digestive enzymes inside of lysosomes help break down proteins, polysaccharides, lipids, nucleic acids, and worn-out organelles. Also helps destroy diseases causing organisms in tandem with your immune system.

Vacuoles

• Membrane bound sacs used for storage and transportation. Vacuoles are larger and what we will talk most about. They do not fuse to membranes of other organelles while vesicles can.

Mitochondria

• The “powerhouse” or “Energy Factory” of the cell. Makes adenosine triphosphate (ATP), which is the main energy carrying molecule for cells. The formation of ATP by breaking down Glucose is called cellular respiration. Mitochondria have their own DNA and Ribosomes.

Ribosomes

• Responsible for protein synthesis.

• Appear as free floating dots in the cytoplasm, but attach to the Smooth ER, turning it into Rough ER when it’s time to make protein.

Cilia

• Cilia are whiplike cellular extensions that move substances along the cell surface.

• Example: Mucus is carried up and away from the lungs by ciliated cells lining the respiratory system.

• Cilia are usually found in large numbers on the exposed cell surface.

• Formation of cilia: Centrioles multiply and line up beneath the plasma membrane, microtubules sprout from the centrioles and put pressure on the membrane, forming the projections.

• If the projections formed by the centrioles are longer, they are called flagella.

• Example: The only flagellated cell in the human body is the sperm, which has a single propulsive flagellum called its tail.

Microvilli

• Microvilli are tiny, fingerlike extensions of the plasma membrane that project from an exposed cell surface.

• They increase the cell's surface area tremendously and are usually found on cells active in absorption, such as intestinal and kidney tubule cells.

• Microvilli have a core of actin filaments that extend into the internal cytoskeleton of the cell and stiffen the microvillus.

DNA Structure

Introduction to DNA

• DNA is organized into structures called chromosomes within the cell.

The Structure of DNA

• A DNA molecule consists of two long strands paired like a ladder, coiled around each other.

• Each strand is a chain of nucleotides bonded together, containing a phosphate, a sugar (deoxyribose), and one of four nitrogen bases (Adenine, Guanine, Cytosine, Thymine).

• The phosphate and sugar form the backbone of the ladder, while the bases bond to form the 'rungs'.

• Adenine pairs with Thymine, and Guanine pairs with Cytosine.

DNA and RNA

Transcription

• Process of copying DNA into mRNA

• Occurs in the nucleus

• RNA polymerase binds to the DNA and separates the DNA strands

• RNA polymerase adds complementary RNA nucleotides to the template strand of DNA

• mRNA is synthesized and detaches from the DNA template

Translation

• Process of synthesizing proteins from mRNA

• Occurs in the cytoplasm

• mRNA binds to a ribosome

• tRNA molecules bring amino acids to the ribosome

• tRNA anticodon pairs with mRNA codon

• Amino acids are joined together to form a polypeptide chain

Organ Systems

Cardiovascular System

• Involves the heart, blood, and blood vessels

• Transports oxygen, nutrients, and other substances to the cells

• Transports wastes, carbon dioxide, and other substances away from the cells

Digestive System

• Involves the salivary glands, esophagus, stomach, liver, gallbladder, pancreas, small intestine, and large intestine

• Processes foods and absorbs nutrients, minerals, vitamins, and water

Endocrine System

• Involves the pituitary gland, pineal gland, thyroid, parathyroid gland, adrenal glands, testes, and ovaries

• Provides communication within the body via hormones

• Directs long-term change over other organ systems to maintain homeostasis

Integumentary System

• Involves the skin, hair, and nails

• Provides protection from injury and fluid loss, and is a physical barrier against infection

• Controls temperature

• Keeps the outside out and the insides in

Lymphatic / Immune System

• Involves the lymph, lymph nodes, and lymph vessels

• Involves the leukocytes, tonsils, adenoids, thymus, and spleen

• Defends against microbial pathogens (disease-causing agents) and other diseases

Muscular System

• Involves the tendons, skeletal, cardiac, and smooth muscles

• Provides movement, support, and heat production

Nervous System

• Involves the brain, spinal cord, nerves, and sensory organs (eyes, ears, tongue, skin, and nose)

• Collects, transfers, and processes information

• Directs short-term change over other organ systems in order to maintain homeostasis

Reproductive System

• Involves the fallopian tubes, uterus, vagina, ovaries, mammary glands, testes, vas deferens, seminal vesicles, prostate, and penis

• Produces gametes (sex cells) and sex hormones, as well as offspring

Respiratory System

• Involves nasal passages, pharynx, larynx, trachea, bronchi, and lungs

• Keeps the body supplied with oxygen and removes carbon dioxide

Skeletal System

• Involves the bones, cartilage, and ligaments

• Supports and protects soft tissues of the body

• Provides movement of joints

• Produces blood cells

• Stores minerals

Urinary / Excretory System

• Involves the kidneys, ureters, urinary bladder, and urethra

• Removes excess water, salts, and waste products from the blood and the body

Interdependence of Organ Systems

Teamwork of Organ Systems

• The organ systems and their specialized cells are designed to all work together to make the body operate as it should

• Like a team, each system must be 'doing their part' in order for the whole to be healthy and executing proper functions

• Although different, one system is not more important than another

• All are necessary to sustain life