LSB142: Introduction to Anatomy and Physiology

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Define Anatomy

Anatomy is the study of the structure and shape of the human body and its parts and their relationship with each other. Split into gross (visible parts) and microscopic anatomy (microscopic).

Define Physiology

Physiology is the study of how the body and its parts function. Has subdivisions like neurophysiology and cardiac physiology

Outline the relationship between anatomy and physiology

Structure determines function. For example, lungs have thin walls so it can effectively exchange gases

State the six levels of structural organization

Chemical level, cellular level, tissue level, organ level, organ system level, organismal level

Explain how the six levels of structural organization are related

Atoms make up molecules which associate to make up cells. Cells with common functions come together to form tissue. Two or more tissue types form organs, which can complete specific, complex functions in the body. Organs together form the organ system which works together to complete a common purpose. Organ systems forms the organism.

Outline the integumentary system and its major functions

Covers the external body and includes the skin, hair and nails. It waterproofs the skin, protects deeper tissues from injury. Produces vitamin D from sunlight. Perspires to excrete salts and regulate body temperature. Has sensory receptors to alert what is happening on body surface.

Outline the skeletal system and its major functions

Consists of bones, cartilages and joints. Supports the body and provides a framework from which the skeletal muscles can cause movement. Has protective functions and cavities of bones produce blood cells. Hard substances of bones act as storehouse for minerals.

Outline the muscular system and its major functions

Contracts to cause movement. Skeletal muscles cause mobility of the body and forms the muscular system. Skeletal muscles are different from other organ muscles

Outline the nervous system and its major functions

The fast acting control system, consisting of the brain, spinal cord, nerves and sensory receptors. Body reacts to external (temp, light, sound) and internal stimuli (O2 levels) via sensory receptors which send nerve impulses to the CNS, which then responds by activating appropriate body effectors.

Outline the endocrine system and its major functions

Slow acting control system. Endocrine glands (pituitary, thyroid, parathyroid, adrenals, thymus, pancreas, pineal, ovaries and testes) produce hormones to release into the blood to travel to distinct target organs. Functions of hormones are varies with some examples being to regulate other structures and the growth, reproduction and use of nutrients by cells.

Outline the cardiovascular system and its major functions

Primary organs include heart and blood vessels. System uses blood as a carrier to deliver oxygen, nutrients, hormones and other substances to, and removes waste like CO2 from cells near sites of exchange. WBCS and chemicals in blood help protect from pathogens and tumors. Heart pumps blood into vessels to be transported.

Outline the lymphatic system and its major functions

Complements the cardiovascular system. Consists of lymphatic vessels, lymph nodes and other lymphoid organs like the spleen and tonsils. Returns fluid leaked into the tissues from the bloodstream, so enough blood can circulate through the body. Lymph nodes and lymphoid organs help cleanse blood and house WBCs

Outline the respiratory system and its major functions

Keeps the body supplied with O2 and removes CO2. Consists of nasal passages, pharynx, larynx, trachea, bronchi and lungs. Alveoli within lungs exchange gas.

Outline the digestive system and its major functions

The alimentary canal. Consists of the oral cavity, eosophagus, stomach, small and large intestines and the rectum. Accessory organs including, liver, salivary glands, pancreas and others. Works together to break down food and deliver the resulting nutriends to the blood to body cells. Breakdown activities begins in mouth, finishes in small intestine. Latter functions to absorb nutrients and water.

Outline the urinary system and its major functions

Disposes waste by-products. Removes nitrogen-containing wastes from blood and flushes them through urine. comprised of kidneys, ureters, bladder and urethra. Another function is to maintain body water and salt balance, regulate acid-base balance and normal blood pressure

Outline the reproductive system and its major functions

To produce offspring. Sperm produced in the testes. Other structures include scrotum, penis, accessory glands and duct system. Eggs produced in the ovaries. Other systems include uterine tubes, uterus and vagina. Uterus the site of development of fetus after fertilization.

Outline the eight functions that humans must perform to maintain life

Maintaining boundaries (inside remains distinct from outside), movement (all activities promoted by the muscular system), responsiveness (ability to sense changes and respond to them), digestion (breakdown of ingested food to be absorbed into the blood), metabolism (all chemical reactions that occur within the body and all its cells), excretion (removal of wastes), reproduction (production of offspring), growth (increase in cell and body size)

List the 5 survival needs of the body

Nutrients, oxygen, normal body temp, atmospheric pressure, water

Describe the anatomical position

Body is standing upright, feet slightly apart, palms facing forward, shoulders and head facing forward. Used as initial reference point and use directional terms.

Homeostasis

Describes the body’s ability the maintain relatively stable internal conditions despite the constantly changing external conditions.

Explain the homeostasis, and why it is important

Homeostatic imbalance can lead to illness. All homeostatic control mechanisms include a receptor, which responds to changes (stimuli), the control center changes and stimulates an effector, producing the response to environmental change

Define negative feedback

Negative feedback mechanisms either shut off the original stimulus or reduce its intensity, and return the body to a state of homeostasis

Define positive feedback

Positive feedback mechanisms increase the original stimulus and push it father from its original value

Explain the function of the plasma membrane

The plasma membrane is a fragile, transparent barrier that contains the cellular contents and separates them from the surrounding environment. The structure is composed of the phospholipid bilayer which controls what passes through the cell, with cholesterol and floating proteins scattered among them. Some phospholipids can have sugars attached, forming glycolipids. The bilayer is fluid, meaning proteins are able to freely move, forming a mosaic like pattern. Hydrophilic head and hydrophobic tail creates a self-orientating property which allows membranes to reseal when torn. Hydrophobic makeup of membrane interior makes membrane impermeable to most water soluble molecules.

It contains cholesterol (keeps membrane stable and flexible), glycocalyx (sticky, sugar rich area) and various proteins, such as channel proteins, glycoproteins (determines blood type, receptors, cell-to-cell recognition), structural proteins and proteins in the cell membrane.

Outline the functions of proteins in cell membranes

Responsible for specialised functions of the membrane. Some act as enzymes, receptors to hormones, binding sites for anchoring, transport

Explain the function of the nucleus

The nucleus contains the genetic material. One of the recognizable regions of the nucleus is the nuclear envelope which has openings called nuclear pores. The nucleolus is the site where ribosomes are assembled. Chromatin is DNA wrapped around histone proteins, when cell is not dividing.

Outline the cytoplasm

Cellular material inside the plasma membrane, site of most cellular activities. Contains cytosol, a semitransparent fluid that suspends other elements, containing water, nutrients and other solutes. Inclusions are chemical substances that could be present depending on cell type, which are stored nutrients floating in the cytosol. Also contains organelles, specialised cellular compartments, many of which are membrane bound.

Mitochondria

Site of aerobic respiration and ATP synthesis. They are rodlike, double-membrane structures, inner membrane folded into projections called cristae

Ribosome

Tiny bodies made of protein and ribosomal RNA. Sites of protein synthesis. Some roam freely within cytoplasm while others are attached to the rough ER, which produce proteins that function outside the cell or on the exterior cell surface. Assembled in the nucleolus and made of a large and small subunit.

Endoplasmic Reticulum

A system of fluid filled tunnels that coil through the cytoplasm. Continuous with the nuclear envelope, and provides network of channels for carrying substances from one part of the cell to another. The rough ER has ribosomes attached and is involved in protein production and modification. The smooth ER is involved in membrane production and functions as hormone production and triglyceride formation

Golgi Apparatus

Stack of membranous sacs associated with swarms of tiny vesicles. Major function to modify, package and ship proteins in specific ways, depending on their final destination. Proteins tagged for export accumulate in the Golgi, and placed into secretory vesicles to travel to the plasma membrane, fusing with it to be ejected outside the cell.

Lysosomes

Membranous sacs containing acid hydrolases, sites of intracellular digestion

Cytoskeleton

elaborate network of protein structures extending throughout the cytoplasm. Determines cell shape, supports other organelles and provides machinery for intracellular transport and carious types of cell movements

passive transport - diffusion

particles moving from an area of high concentration to an area of low concentration, moving down the concentration gradient

simple diffusion

the unassisted diffusion of solutes through the plasma membrane, usually done with lipid soluble solutes

osmosis

the diffusion of water through a selectively permeable membrane such as the plasma membrane, passes through aquaporins in the membrane

facilitated diffusion

provides passage for lipid-insoluble and large molecules through protein channels, can be active as well

filtration

process by which water and solutes are forced through a membrane by hydrostatic pressure, usually exerted by blood, moving down a pressure gradient from an area of high pressure to an area of low pressure

active processes

moving against the concentration gradient, thus requiring ATP

active transport - vesicular transport

exocytosis, endocytosis, phagocytosis, pinocytosis

name the 4 primary tissue types

epithelial, connective, nervous and muscle

epithelial tissue function

protection, absorption, filtration and secretion. Includes epithelia (covering tissues) and glands (secretes chemicals). All epithelia have apical (facing outside) and basal (facing deeper cells) surfaces. Classified into simple (single cell layer) and stratified (multiple cell layers). Shapes include squamous (almost flat), cuboidal (similar height and width), and columnar (tall and skinny)

simple squamous epithelium

single layer of flattened cells, resting on a basement membrane. Example: alveoli of lungs

Simple cuboidal epithelium

one layer of cuboidal cells resting on a basement membrane, found in walls of kidney tubules

simple columnar epithelium

single layer of columnar cells, with nuclei formed in a straight line, found in ducts of kidneys

Stratified squamous epithelium

consists of many cell layers, most common type, cells at free edge are squamous while those close to basement membrane are cuboidal or columnar, found where there is lots of abuse like mouth, skin and esophagus

stratified cuboidal epithelium

typically at least two cell layers, with surface cells being cuboidal in shape

stratified columnar epithelium

surface cells are columnar but basal cells vary in shape and size

transitional epithelium

highly modified, stratified squamous epithelium that forms lining of few organs - the urinary bladder, ureters and part of urethra

connective tissue function

provides strength to resist external forces, protects internal organs, maintains proper organ shape, provides a framework for muscle movement

main classes of connective tissue

major classes: connective tissue proper, cartilage, bone and blood

All contain cells and extracellular matrix

Connective tissues contain extracellular fibers, different type determines mechanical properties

• collagen fibers - strong and resistant to stretch, provides tensile strength

• reticular fibers - thinner, provide structural framework to keep cells in place

• elastic fibers - stretch and spring back, provides elasticity to tissues

connective tissue proper - loose connective tissue function

contains cells and an extracellular matrix with fibers, the three types include: areolar, reticular and adipose

Areolar connective tissue

• found throughout the body beneath epithelial tissue

• provides support, strength and elasticity

• contains collagen, reticular and elastic fibers

• plays a role in inflammation and immune system function

reticular connective tissue

• contains reticular fibers

• found in lymph nodes, bone marrow and spleen (lymphatic organs)

• provides a framework for blood-forming cells and immune defenses

adipose tissue

• consists mainly of fat cells

• functions as a fuel reservoir, thermal insulation and organ cushioning

Connective tissue proper - dense connective tissue function

has few cells and an extracellular matrix primarily composed of fibers, has three types

• regular dense connective tissue

• irregular dense connective tissue

• dense elastic connective tissue

regular dense connective tissue

• parallel collagen fibers

• found in tendons and ligaments

• offers great tensile strength along the fiber direction

irregular dense connective tissue

• collagen fibers in various directions

• resists stretching forces from different directions

• found in the dermis and fibrous capsules around joints

dense elastic connective tissue

• abundant elastic fibers

• highly elastic

• found in the walls of airways and large arteries

cartilage functions

• part of the skeleton, found on ends and between bones

• provides support, flexibility and minimizes friction

• chondroblasts secrete cartilage’s extracellular matrix

• extracellular matrix contains collagen fibers and proteoglycan molecules

• high water content in cartilage contributes to its resistance to compressions and low friction

types of cartilage

1. hyaline cartilage

   • forms smooth covering on long bone ends

   • found in ribs, nose, trachea and larynx

2. elastic cartilage

   • contains more elastic fibers, allowing bending and springing back

   • found in external ear and epiglottis

3. fibrocartilage

   • contains more collagen fibers, providing tensile strength

   • found in intervertebral discs and knee menisci

bone (osseous tissue) function

• protects organs and supports the body

• provides a rigid framework for muscle attachment

• osteoblasts secrete bone’s extracellular matrix

• extracellular matrix contains collagen fibers for tensile strength and calcium salts for hardness and compressive strength

muscle tissue function

• allows body movement and generates force

• uses actin and myosin proteins to generate force and requires ATP for contraction

• three types of muscle tissue: skeletal, cardiac and smooth

• skeletal and cardiac muscle are striated

Skeletal muscle function

• pulls on bones for movement

• long and thin cells with multiple nuclei

• striations at right angles to the cell’s long axis

cardiac muscle function

• found in the heart

• shorter cells with high mitochondria content for continuous ATP generation

smooth muscle

• found in walls of hollow organs

• uniform appearance under a light microscope

Nerve tissue function

• conveys information through electrical signaling

• concentrated in the brain and spinal cord, extends throughout the body

• peripheral nervous system includes nerves outside the central nervous system

• peripheral nervous system has motor commands for muscles, glands and sensory signals from various sensory organs

nerve tissue structure

• contains glial cells and neurons

• neurons have a compact cell body and extensions for transmitting and receiving electrical signals