Body Organization and Homeostasis PDF

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Joyce Kille-Marino
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Body Organization and Homeostasis September 7, 2018 2:44 PM

Overview: o o o o

Anatomy vs. Physiology (COMPLIMENTARY NATURE OF FORM AND FUNCTION) Levels of organization Homeostasis Language of Anatomy

What is A&P? Anatomy: study of the structure of body parts and their relationship to one another o gross (macroscopic) - large structures visible with unaided eye o microscopic - structures cannot be seem with naked eye and need magnification Physiology: study of functions of anatomical structures (individual and co-op functions) Form and function have a complimentary nature! What are the basic functions of all living things? o Respond to changes o Adapt to changes o Grow, develop, and reproduce o Capable of some degree of movement (from one place to another = locomotion) Characteristics of living organisms: Characteristic

Importance

Notes

Responsiveness

Indicates that the organism recognizes changes in it's internal or external environment

Required for adaptability

Adaptability

Changes the organism's behavior, capabilities, or structure.

Required for survival in a constantly changing world

Growth and development

Inherited patterns for growth and development produce organisms characteristic of their species.

Growth and development to maturity is controlled by inherited instructions in the form of DNA

Reproduction

Produces the next generation

Sexual reproduction between two parents produces offspring with varied characteristics

Movement and locomotion

Distributes materials throughout large organisms; changes orientation or position of a plant or immobile animal, moves mobile animals around the environment

Animals show locomotion at some point in their lives

Respiration *

Usually refers to oxygen absorption and utilization and CO2 generation and release

Oxygen is required for chemical processes that release energy in a usable form; CO2 is released as a waste product.

Circulation *

Movement of fluid within the organism; may involve a specific pump and network of specific vessels

Provides internal distribution network

Digestion *

The chemical breakdown of complex materials Chemicals released can be used to for absorption and use by org. generate energy or support growth

Excretion *

Elimination of chemical waste products generated by the organism

The waste products are often toxic, so their removal is essential

*the mechanics of the process depends on the size and complexity of the organism

Levels of Organization: Each level is more complex than the underlying one! Organism - highest level of organization; all organ systems of an organism's body work together to maintain life and health Organ system - organs interact in organ systems Organ - an organ consists of two or more tissues working to perform several functions. Tissue - a tissue is a group of cells and cell products working together to perform one or more specific functions. Cellular - cells are the smallest living units in the body; their functions depend on organelles which have specific functions. Chemical - atoms the smallest stable unit of matter can combine to form molecules with complex shapes; functional prop. are determined by shape and atomic components

Cells are the smallest units of life Free living cells are the smallest living structures with the four characteristics discussed earlier. Most organisms are multi-cellular; the cells work together, each with its own characteristics and functions. The human body contains about 200 different cell types (dimensions given in micrometers - 1/25000 of an inch). Some types of cells: o Smooth muscle cells - found in many organs; are long and slender o Blood cells - either flattened discs (RBC - transport oxygen and carbon dioxide in blood) or roughly spherical (WBC - responsible for fighting off disease and infection) o Bone cells - reside within small cavities in bone; maintain bone and recycle calcium and phosphate stored in bone o Fat cells - spherical storage containers; excess energy obtained from food gets stored as fat; these cells get larger and more numerous o Cells lining digestive tract - delicate; absorb nutrients, vitamins, minerals, and water we need o Reproductive cells - cells involved in sexual reproduction; women = large oocytes in small numbers and monthly intervals; males - continually produce tiny sperm o Nerve cells (aka neurons) - process information; has extensive branching which provides huge surface areas to communicate with other neurons.; transmit signals. Basic principles of cell theory: o cells are the structural building blocks of all plants and animals o cells are produced by the divisions of pre-existing cells o cells are the smallest structural units that perform all vital functions. Tissues are specialized groups of cells and cell products Different cell types and cell products combine to form tissues that perform specific functions. Histology - study of tissues There are 4 primary tissues types: o Epithelial tissue  most common type is a layer of cells that form a barrier with specific properties; covers and protect exposed surfaces; lines internal passageways and chambers, produces glandular secretions. o Connective tissue  diverse in appearance; contain cells and an extracellular matrix made of protein fibers and a liquid aka ground substance (consistency of matrix depends on type of tissue; blood = watery; bone = durable)  fills internal space, provides structural support, and stores energy o

Muscle tissues  individual muscle cells con contract forcefully (unique) to produce active movement

 major functions include skeletal movement, soft tissue support, maintenance of blood

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flow, movement of materials along internal passageways, and stabilization of body temperature  Three types of muscle tissue:  Skeletal - attached to skeleton (directly/indirectly); when it contracts, it moves/stabilizes position of bones/organs  Cardiac - coordinated contractions propel blood through blood vessels  Smooth - along walls of blood vessels, within glands, and along respiratory, circulatory, digestive, and reproductive tracts. Neural tissue  specialized to carry information from one place in body to another; broken up into CNS (brain and spinal cord) and PNS (nerves connect CNS with other tissues and organs)  Two types:  Neurons (nerve cells) - transmit info in form of electrical impulses  Neuroglia (supporting cells) - isolate and protect neurons; form framework

Organs and organ systems perform vital functions Organ - functional unit composed of more than one tissue type; combination and organization determine organ's functions. Organ system - organs that interact to perform a specific range of functions (often coordinated) 11 Organ Systems of the Body: o

Integumentary  Protects against env. hazards; helps control body temp.  Organs:  cutaneous membrane (epidermis - covers surface + protects tissues; dermis nourishes epidermis, provides strength and contains glands)  hair follicles (produce hair, innervation provides sensation)  hairs - protect head  sebaceous glands - secrete lipid coating that lubricates hair shaft and epidermis  sweat glands (perspiration for cooling)  nails (protect and stiffen distal tips of digits)  sensory receptors (provide sensations of touch, pressure, temp., pain)  hypodermis (stores lipids; attaches skin to deeper structures)

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Skeletal  Provides support; protects tissues; stores minerals; forms blood cells  Organs:  bones, cartilages, and joints (support, protect soft tissues; bones store minerals)  axial skeleton - incl skull, vertebrae, sacrum, coccyx, sternum, supporting cartilage and ligaments- (protects brain, spinal cord, sense organs, and soft tissues of thoracic cavity; supports the body weight over lower limbs.

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Appendicular skeleton - limbs and supporting bones and ligaments provides internal support and positioning of the limbs; supports and moves axial skeleton bone marrow (primary site of blood cell production - red marrow; stores of energy in fat cells - yellow marrow)

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Muscular  Produces movement; provides support; generates heat  Organs:  skeletal muscles (provide skeletal movement; control entrances to digestive and resp. tracts and exits from digestive and urinary tracts; produce heat; support skeleton; protect soft tissue)  axial - support and position axial skeleton  appendicular - support, move, and brace limbs  tendons, aponeuroses (uses forces of contraction to perform specific tasks)

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Nervous  Directs immediate response to stimuli via coordinating activity of other organ systems  Organs:  CNS (acts as control center for nervous system; processes information; provides short term control over activities of other systems)  brain - performs complex integrative functions; controls both voluntary and involuntary activities  spinal cord - relays information to and from the brain; performs less complex integrative activities  special senses - provide sensory input to the brain relating to sight, hearing, smell, taste, and equilibrium  PNS (links CNS with other systems and with sense organs)

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Endocrine  Directs long-term changes in other organ systems  Organs:  Pineal gland - may control timing of reproduction and set day-night rhythms  Pituitary gland - controls other endocrine glands; regulates growth and balance fluid  Thyroid gland - controls tissue metabolic rate; regulates calcium levels  Parathyroid gland - regulate calcium levels with thyroid gland  Thymus - controls maturation of lymphocytes  Adrenal gland - adjust water balance, tissue metabolism, cardiovascular and respiratory activity  Kidneys - control RBC production, elevate blood pressure, and assist in calcium homeostasis.  Pancreas - regulates blood glucose levels  Gonads  testes - support male sex characteristics and reprod.  ovaries - support female sex characteristics and reprod.

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Cardiovascular

 Transports cells and dissolved materials including nutrients, wastes, and gases  Organs:  heart - propels blood; maintain blood pressure  blood vessels - distribute blood around body  arteries - carry blood from heart to capillaries  capillaries - permit diffusion between blood and interstitial fluids  veins - return blood from capillaries to heart  blood - transports oxygen, CO2, and blood cells; deliver nutrients and hormones;

removes wastes; assists in temp. regulation and defense against disease o

Lymphatic  Defends against infection and disease; returns fluid to the bloodstream  Organs:  lymphatic vessels - carry lymph (water + proteins) and lymphocytes from peripheral tissues to veins of Cardio system  lymph nodes - monitor the composition of lymph; engulf pathogens; stimulate immune response  spleen - monitor circulating blood; engulfs pathogens and recycle RBC; stimulates immune response  thymus - controls development and maintenance of T-cells (one type of lymphocytes)

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Respiratory  Delivers air to sites where gas exchange occurs between air and circulating blood; produces sound  Organs:  nasal cavities and paranasal sinuses - filter, warm, humidify air; detect cells  pharynx - conducts air to larynx; a chamber shared with digestive tract  larynx - protect opening to trachea and contains vocal cords  trachea - filters air; cartilages keep airway open  bronchi - conducts air between trachea and lungs  lungs - responsible for air movement; alveoli within the lungs are sites of gas exchange between air and blood.

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Digestive  Processes food and absorbs nutrients  Organs:  mouth - cavity for food; works with assoc. structures to break up food and pass food and liquids to pharynx  salivary glands - provide buffers and lube; produce enzymes that begin digestion  pharynx - conducts solid food and liquids to esophagus (chamber shared with resp. tract)  esophagus - delivers food to stomach  stomach - secretes acids, enzymes and hormones  small intestine - secretes digestive enzymes, buffers and hormones; absorbs nutrients  liver - secretes bile; regulates nutrient composition of blood  gallbladder - stores and concentrates bile for release into small intestine

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pancreas - secretes digestive enzyme and buffers; contains endocrine cells large intestine - removes water from feces; stores wastes

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Urinary  Eliminates xs water, salts and wastes; controls pH  Organs:  kidneys - form and concentrate urine; regulate blood pH and ion concentrations; perform endocrine functions  ureters - conduct urine from kidneys to urinary bladder  urinary bladder - stores urine for eventual elimination  urethra - conducts urine to exterior

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Reproductive  Produces sex cells and hormones; supports embryonic dev from fertilization to birth.  Female organs:  ovaries - produce oocytes and hormones  uterine tubes - deliver oocyte or embryo to uterus; normal site of fertilization  uterus - site of embryonic development; exchange between maternal and fetal bloodstream; shed lining in menstruation  vagina - site of sperm deposition; birth canal; passage for menstrual fluids  external genitalia  clitoris - contains erectile tissue; pleasure sensations  labia - contains glands that lubricate entrance to vagina  mammary glands - produce milk  Male organs:  testes - produce sperm and hormones  accessory organs  epididymis - acts as site of sperm maturation in each testis  ductus deferens - conducts sperm from epididymis  seminal glands - secrete fluid that contributes to semen  prostate gland - secretes fluid and enzymes  urethra - conducts semen to exterior  external genetalia  penis - deposits sperm in vagina  scrotum - surrounds testes and controls their temp.

SO, organs of .. Integumentary, skeletal and muscular systems support and move the body Nervous system provides rapid control and regulation Endocrine system secretes chemicals that are carried by the cardiovascular system Lymphatic system defends the body Respiratory system exchanges vital gas Digestive system makes nutrients available and with urinary system excretes wastes Reproductive system provides continuity of life

Homeostasis:

Ability to maintain a stable internal environment. o stay within narrow limits to maintain life o allow body to maintain its physiological parameter in a normal range (predetermined set point) o Failure to maintain homeostasis -> Illness or Death Often controlled by feedback mechanisms - primarily -ve feedback: o Feedback REQUIRES 3 parts:  Sensor - sensitive to particular change or stimulus  Control Center - receives and processes information from stimulus and sends out commands  Effector Organ - responds to commands by opposing the stimulus -> homeostasis

Ex. Homeostasis of Body Temp Too Cold - shunt our blood to core organs and decrease blood flow on surface (to decrease heat loss); initiate shivering Too Hot - shunt blood towards surface to allow sweating and cooling. So, sensor will detect temperature; control center will send messages to effect proper response to either heat or cool accordingly.

Feedback regulation

Primary means the body uses to maintain homeostasis. Depends on the constant flow of info from sensors to appropriate control center to make corrections for deviations from a normal "set point" Types of FR: Negative feedback: MINIMIZES CHANGE o Effector activated by the control center opposes or negates the original stimulus o Stabilizing (returns system to normal set point) o Ex. Temp regulation; reg of blood CO2 level; regulation of blood glucose level Positive Feedback: ACCELERATES SPECIFIC BODY FUNCTIONS TO COMPLETION - makes things worse before they get better! o initial stimulus produces a response that exaggerates or enhances the change in original conditions, rather than opposing it. o can result in escalating cycle aka positive feedback loop o Ex. blood clotting; child birth; disease state - cardiac failure.  Blood clotting - damage to cells in blood vessel release chemicals to start clotting; chemicals start rxns so proteins in blood start to forma clot; clotting continues releasing chemicals each step which accelerates clotting; ends with formation of blood clot and cessation of bleeding.  Child birth - at start of labour, child’s head is pushed through cervix which releases oxytocin (causes uterine contractions), cervix being open --> oxytocin, deliver child as fast as possible to return body to "normal"  Sometimes a disease state can occur with a positive feedback loop - cardiac failure inability to pump normal amount of blood, blood is left behind, stretches out the heart and the condition gets increasingly worse.

Language of Anatomy

*ALWAYS refer to anatomical position*

Anatomical position o o

is body erect with arms at sides, palms forward, heat and feet pointing forward used as a standard point of reference  supine (lying on back in anatomical position - face up)  prone (lying face down)

Body planes, sections and directional terms o

Directional and sectional terms describe specific points of reference:

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Sectional Terms:  Sagittal plane - divides body into left and right halves  can be midsagittal (through midline) or parasagittal (unequal left and right halves)

 Frontal (coronal) plane - divides the body into anterior (front) and posterior (back)

halves  Transverse (horizontal) plane - divides the body into superior (top) and inferior (bottom)

halves (creates cross section) o

Directional Terms:              

Superior- toward the head end or above Inferior – away from the head end or below Cephalic (Cranial) – Towards the head end (more often used in animals who stand on 4 legs) Caudal – Towards the tail end; ends at bottom of torso (more often used in animals who stand on 4 legs) Anterior (ventral) – Towards the front of the body Posterior (dorsal) – Towards the back (rear) Medial – Towards the midline, away from the sides Lateral – Towards the sides, or away from the midline

Ipsilateral - same side of body Contralateral - opp. side of body Proximal – Towards the trunk (used for relative position along a limb) Distal – Away from the point of attachment to the trunk Superficial – Towards or at the body surface Deep – Away from the body surface, more internal

* dorsal/ventral for 4-legged animals *

Body region and regional terms o o

Axial subdivision (head, neck, torso) Appendicular (upper extremity, lower extremity)

Body quadrants o

There are multiple ways to refer to abdominal positions 

The 4 abdominopelvic quadrants: Right upper Q; Left upper Q; Right lower Q; Left lower Q

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The 9 abdominopelvic regions: right hypochondriac; epigastric; left hypochondriac; right lumbar; umbilical; left lumbar; right inguinal; hypogastric; left inguinal

Body cavities o

True body cavities are closed, fluid-filled chambers; they are lined by a serous membrane (serous cells secrete lubricant into cavity - named for specific cavity and organ they're associated with) and share common embryonic origin.   

Lining of peritoneal cavity is peritoneum - Parietal peritoneum and visceral peritoneum in ventral body cavity Lining of pleural cavity aka pleura - parietal pleura and visceral pleura in pleural cavities Lining of pericardial cavity is pericardium - parietal pericardium and visceral pe...