Systems of the Human Body Systems of the

Systems of the Human Body

Systems of the Body • Groups of organs and tissues working together to perform jobs. Certain organs may be involved in more than one system serving multiple purposes • All systems are necessary for life

Functions • Take in oxygen for cellular respiration and give off CO 2 • Ingest and process food • Transport substances (Oxygen, nutrients) • Clear toxic waste • Respond to environment • Fight infections • Protect body’s organs from environment • Reproduce

List of Systems • • • Respiratory System Digestive System Cardiovascular or Circulatory System Urinary System Endocrine System Nervous System Musculoskeltal System Integumentary System/Exocrine Lymphatic/Immune System Reproductive System

Respiratory System • Main function: Take in oxygen-Give off carbon dioxide – 12 to 24 times per minute you breathe (pulmonary ventilation) without even knowing it • Primary organs are the lungs which carry out the exchange of gases • Red blood cells are transporters • Decrease in oxygen is called hypoxia. Complete lack of oxygen is called anoxia • After 4 minutes without oxygen, brain cells begin to die

Respiratory System Starts at nose or mouth Travels down throat to trachea (windpipe) Air divides to passages call bronchial tubes As tubes pass through lungs, passages divide again into bronchioles • Bronchioles end in tiny balloon sacs called alveoli (You have about 300 million) • Alveoli are surrounded by tiny blood vessels called capillaries • •

Respiratory System • The oxygenated blood leaves the lungs and travels to the heart • Once cells use the O, the RBC carry the CO 2 back to the lungs for exhalation • The Diaphragm is a muscle underneath the lungs aiding in breathing

Respiratory System • Air stays clean by – Nose hair, – Cilia along the air passages – Mucus • Cigarette smoke may stop cilia from functioning properly

Respiratory System • Pharynx referred to as the throat – Serves in digestive system too – Upper part allows only air to pass – Lower part permits air, food, and fluid • Larynx is called the voice box – Passageway of air between pharynx and trachea • Trachea is main airway to lungs – Lined with mucous membrane

Respiratory System • Lungs contain the bronchial tree • Mostly soft and spongy because mostly air spaces • Two lungs

Cardiovascular System • Consists of heart, blood vessels and approximately 5 liters of blood • Transports oxygen, nutrients, hormones, and cellular waste • Powered by the heart-the body’s hardest working organ • Size of a closed fist

Cardiovascular System • 2 primary circulatory loops – Pulmonary circulation transports deoxygenated blood from right side of heart to lungs – Blood picks up oxygen and returns to left side of heart – Systemic Circulation carries highly oxygenated blood from left side of the heart to rest of the body (except lungs and heart) – Removes waste from body tissues and returns deoxygenated blood to right side of heart

Cardiovascular System • Blood vessels are the “highways” of the body for blood to flow • All blood vessels contain a hollow area for blood to flow • There are 3 major types of blood vessels – Arteries, capillaries, and veins

Cardiovascular System • Arteries are blood vessels that carry blood away from the heart • Blood is usually highly oxygenated because the blood just left the lungs – Only time blood is deoxygenated in arteries is when the blood travels from the heart to the lungs • Artery walls are thicker, more elastic, and more muscular-Undergo great force • Arterioles are narrower arteries that branch off at the ends of arteries and carry blood to capillaries

Cardiovascular System • Capillaries are the smallest and thinnest blood vessels. • Found in almost every tissue of the body • Exchange gases, nutrients, and waste products with cells • Thin walls to diffuse along concentration gradient

Cardiovascular System • Veins are the large return vessels of the body • Veins have very low BP • Walls of veins are much thinner, less elastic, less muscular compared to arteries • Veins rely on gravity, inertia, and skeletal muscle contractions • Veins contain one way valves • Venules are smaller veins carrying blood from the capillaries to larger veins back to the heart

Cardiovascular System • Average body contains 4 -5 liters of blood • Red blood cells (erythrocytes) make up 45% of blood volume • Biconcave disks with concave curve to fold to fit into capillaries • Transport O through red pigment of hemoglobin • Hemoglobin has iron and proteins to increase O carrying capacity

Cardiovascular System • White blood cells (leukocytes) make up small percentage of cells in blood stream • Play major role in immune system • Neutralize bacteria invading the body, digest viruses, protect against parasites • T cells and natural killer cells fight off viral infections, produce antibodies, engulf and ingest pathogens around wounds or infections

Cardiovascular System • Platelets (thrombocytes) are responsible for clotting of blood and formation of scabs – Only last about a week in the body before leukocytes (macrophages) capture and digest them • Plasma is liquid portion of the blood (55% of volume) • Mixture of water, proteins, and dissolved substances • Proteins are albumins and antibodies. Antibodies help in the immune system. Albumin helps maintain osmotic balance • Dissolved substances are glucose, oxygen, CO 2, electrolytes, nutrients, and waste products

Cardiovascular System • Functions include transportation, protection, and regulation • Transport-Nutrients, O, CO 2, hormones • Protect-WBC clean up debris and fight pathogens. Platelets and RBC form scabs to seal wounds to prevent pathogens entering body. Blood carries antibodies to previously exposure or from vaccinations. • Regulate-Maintain homeostasis. Body temperature. Balance p. H

• The heart has four chambers: two atria and two ventricles. • The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. • The right ventricle pumps the oxygen-poor blood to the lungs. • The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle. • The left ventricle pumps the oxygen-rich blood to the body.

Digestive System • Made up of gastrointestinal tract (GI tract) and liver, pancreas, and gallbladder • GI tract-Hollow organs are mouth, esophagus, stomach, small intestine, large intestine, and anus • Solid organs are liver, gall bladder, and pancreas

Digestive System • Need nutrients from food and drink-proteins, fats, carbohydrates, vitamins, minerals, and water • Breaks food down into small parts so body can use for energy, growth, and cell repair • Proteins become amino acids • Fats become fatty acids and glycerol • Carbohydrates become glucose then glycogen

Digestive System • Mouth-Mastication (chewing), saliva-enzyme breaks down starches in food, start of the process • Esophagus-Peristalsis to the stomach – Peristalsis: involuntary constriction and relaxation of muscles to push contents forward • Stomach-Stomach acid and enzymes break down food. Combines to form chyme and empties into small intestine. – Stomach can stretch after eating. The size usually stays the same once reaching adulthood. • Pancreas-Has a digestive juice containing enzymes to break down CHO, fat, and protein

Digestive System • Liver-Digestive enzyme called bile to digest fats and vitamins • Gallbladder stores bile between meals • Small intestine-Major part of digestive process. Small intestine digestive juice mixes with pancreatic juice and bile to continue breakdown. SI absorbs most of the nutrients. Bacteria in SI breakdown CHO. Peristalsis continues to LI • Liver-From the SI, blood carries sugars, amino acids, glycerol, and vitamins to liver for storage, processes, and delivery

Digestive System • Large Intestine-Also called colon. Absorbs water and changes waste from liquid into stool. Other water is absorbed in blood stream. Peristalsis continues to rectum • Rectum-Lower part of LI. Stores stool until pushed out

Digestive System • Hormones tell your brain when you are full or hungry. • Hormones tell stomach and small intestine when to make digestive juices • Nerves connect central nervous system with digestive system. When you see food, your mouth begins to water • Nervous system helps move food and produce digestive juices

Urinary System • Consists of kidneys, ureters, urinary bladder, and uretha • Function to filter and eliminate waste and maintain homeostasis • Kidneys-pair of bean shaped organs. Filter metabolic wastes, excess ions, and chemicals from blood to form urine • Ureters-pair of tubes carrying urine from kidneys to bladder about 10 -12” long. Gravity and peristalsis move urine.

Urinary System • Urinary bladder is a sac-like hollow organ used to store urine. Enters slowly and stretches elastic walls allowing the bladder to stretch from 600 -800 milliliters • Uretha is the tube urine passes from the bladder to outside of the body

Urinary System • Kidneys excrete K, Na, Ca, Mg, and Cl ions when levels are higher than normal concentration. Kidneys can also conserve these ions when lower than normal by reabsorbing into the blood. • Kidneys monitor blood pressure. If BP is high, kidneys reduce volume of blood and excrete more water. If BP is low, more water remains in blood.

Endocrine System • Made up of glands that produce and secrete hormones regulating growth, metabolism (physical and chemical processes of the body), and sexual development and function • Hormones travel through the blood stream • Major glands of the endocrine system include the hypothalamus, pituitary gland, thyroid, parathyroid, adrenals, pineal body, and ovaries/testicles • Pancreas plays major role in endocrine system

Endocrine System • Regulated by feedback • Hypothalamus sends hormone to pituitary gland to release a hormone to be sent to the target gland • The gland then releases another hormone • Hypothalamus and pituitary gland regulate how much hormone is in regulation

Endocrine System • Hypothalamus is located in lower central part of brain. Regulates satiety, metabolism, and body temperature • Secretes hormones to stimulate or suppress hormones in pituitary gland

Endocrine System • Pituitary gland is located in the brain below the hypothalamus and divided into the anterior and posterior lobes • Considered most important because of its control of other glands- “The Master Gland” • Important hormones – Growth hormone stimulates bone and tissue growth – Luteinizing hormone and follicle stimulating hormone produce sex steroids in males and females – Prolactin stimulates milk production – Antidiuretic hormone controls water loss by kidneys

Endocrine System • Thyroid Gland is located in lower front part of neck and regulates metabolism and helps development of bone growth, the brain, and nervous system • Maintain normal BP, HR, digestions, and reproductive functions • Pituitary gland controls release of thyroid hormones

Endocrine System • Parathyroid glands located in pairs on each side of the thyroid gland – Parathyroid hormone plays a role in regulating calcium levels in blood and bone metabolism • Pineal body is located in the middle of the brain – Secretes hormone called melatonin regulating wake-sleep cycle

Endocrine System • Adrenal glands are triangular shaped located on top of each kidney • Produce hormones called corticosteroids (steroids) regulating metabolism, balance of salt and water, the immune system, and sexual function • Produce catecholamines helping body cope with physical and emotional stress by increasing HR and BP(epinephrine/norepinephrine) • Epinephrine and norepinephrine are more commonly known as adrenaline

Endocrine System • Males-testes produce testosterone affecting sexual development and hair and also produce sperm • Females-ovaries produce the hormones estrogen and progesterone and eggs • Control development of breast development and reproductive functions during pregnancy and the menstrual cycle

Endocrine System • Pancreas located behind the stomach • Has digestive and hormonal functions • Secretes insulin and glucagon regulating the level of glucose in blood

Nervous System • Consists of the brain, spinal cord, sensory organs, and all of the nerves connecting the organs with the rest of the body • Responsible for control of the body and communication • Central nervous system is the brain and spinal cord – Injury to the spinal cord can result in paralysis • Peripheral nervous system is the sensory organs and sensory nerves

Nervous System • NS is made up of two types of tissue called neurons and neuroglia • Neurons, also called nerve cells, communicate by transmitting electrochemical signals – Nerve impulses can travel up to 250 mph • 3 Types of neurons – Afferent transmit sensory signals – Efferent transmit signals to effect muscles and glands – Interneurons work between both afferent and efferent by processing information from afferent and signaling to efferent to direct different functions

Nervous System • Brain contains approximately 100 billion neurons • Control center of the body processes consciousness, memory, planning, voluntary actions, respiration, HR, BP, and digestion • Spinal cord is a long, thin bundle of neurons carrying information through vertebrae of spine • Nerves are bundles of axons carrying signals between the brain, spinal cord, and rest of the body – 12 cranial nerves – 31 Spinal nerves – Afferent, efferent, and mixed nerves

Nervous System • 3 main functions of the NS – Sensory function collects information monitoring internal and external conditions – Integration function is the processing of the many sensory signals passed to the central nervous system. Signals are evaluated, compared, used for decision making, discarded or committed to memory – Motor function effects smooth, cardiac, or skeletal muscle or glandular tissue. The body will then release a hormone or move part of the body to respond to the stimulus

Nervous System • Central NS consists of brain and spinal cord. Control center of the body. Uses sensory information to make conscious and subconscious actions to maintain homeostasis. Responsible for higher functions such as language, expressions, creativity, emotions, and personality • Peripheral NS-Includes all parts of the NS outside of the brain and spinal cord • Peripheral NS has 2 divisions-Somatic and Autonomic • Somatic is used for voluntary movement of the muscles • Autonomic is responsible for involuntary movement such as visceral muscle, cardiac muscle, and glandular tissue • Sympathetic-fight or flight response • Parasympathetic-rest and digest • Enteric NS responsible for regulating digestion. May receive information from CNS but works independently. Has as many neurons as the spinal cord

Nervous System • The brain has 3 major parts • Cerebrum: is the largest part of the brain and is composed of right and left hemispheres. It performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement. • Cerebellum: is located under the cerebrum. Its function is to coordinate muscle movements, maintain posture, and balance. • Brainstem: acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. It performs many automatic functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing.

Musculoskeletal System • Consists of bones, cartilage, ligaments, and muscles • 206 bones in adult body provide 5 main functions • Provide support • Store minerals (calcium) and lipids • Produce blood cells-In bone marrow, red blood cells, white blood cells, and other blood elements are produced in the internal cavities of the bone. • Protect body organs • Provide leverage and movement

Musculoskeletal System • Bones consists of both compact and spongy bone • Compact is found on the external while spongy is on the inside • Compact bone is thickest where bone receives stress • Spongy bone is where bone is not stressed or receives stress from many different directions • Spongy bone is much lighter than compact bone

Musculoskeletal System • Skeleton has 2 parts-Axial and Appendicular • Axial-central core of the body. – Protects vital organs-Skull, vertebrae, ribs, sternum – 80 Bones • Appendicular-functions include grasping/manipulating objects and locomotion – shoulder girdle (clavicle/scapula), upper limbs (humorous, ulna, radius) , pelvic girdle (pelvis), lower limbs (femur, patella, tibia, fibula) – 126 bones

Musculoskeletal System • Tendons connect muscle to bone. As muscles contract, the tendon transmits the force to the bone causing movement. • Ligaments connect bone to bone • Cartilage is a type of connective tissue. Hyaline cartilage is found on the tips of ribs to provide stiff but flexible support. Elastic cartilage is found in the ear for flexibility and to tolerate distortion. Fibrocartilage is found with in the knee joint and vertebrae to prevent bone to bone contact, resist compression, and limit relative movement • Cartilage repairs very poorly

Musculoskeletal System • Muscles produce contractions to move body parts, support the body, stabilize joints, and produce body heat • 3 types of muscles-skeletal, cardiac, and smooth (visceral) • Skeletal muscle moves bones (biceps, triceps, pectoralis, gluteus maximus, gastrocnemius) • Cardiac muscle forms walls of the heart and adjacent vessels such as the aorta • Smooth muscle form part of the walls of vessels or hollow organs to move substances

Integumentary (Exocrine) System • Consists of the skin, hair, nails, and exocrine glands • Skin is only few millimeters thick but it is the largest organ of the body covering 20 square feet and weighing 10 pounds • Protect against chemicals, disease, UV light, and physical damage • Exocrine glands produce sweat, oil, and wax to cool, protect, and moisturize

Integumentary System • Epidermis is most superficial layer of skin covering entire body about 1/10 mm thick – Contains no blood or blood vessels • Dermis tissue is below epidermis contains nervous tissue, blood, and blood vessels – Much thicker than epidermis giving skin strength and elasticity • Hypodermis is loose connective tissue under the dermis. Serves as flexible connection between skin and underlying muscles and bones. Also fat storage area for energy use and insulating the body •

Integumentary System • Hair made up of dead keratinocytes found in most areas of body • Protects against UV radiation and insulates body • Two types of sweat glands – Eccrine sweat glands are in almost every region of the skin secreting water and sodium chloride used to lower body temperature – Apocrine sweat glands are found in axillary and pubic regions. Not active until puberty. Then start to produce thick, oily liquid consumed by bacteria on skin

Integumentary System • Sebaceous glands produce oily secretion called sebum to waterproof and increase elasticity of skin • Ceruminous glands produce waxy secretion to trap foreign material from entering ear canal. Wax is made continuously.

Lymphatic System • Network of tissues and organs that help rid the body of waste, toxins, and other materials • Transports lymph throughout the body – Lymph is a clear and colorless fluid containing lymphocytes • Consists of lymphatic vessels similar to circulatory system of veins and capillaries • Hundreds of lymph nodes in body located deep inside such as in the heart or lungs but also closer to the surface – Lymph nodes swell in response to infection due to a build up of lymph fluid, bacteria, or other organ • Tonsils, adenoids, spleen, and thymus are part of lymphatic system

Lymphatic System • The spleen is on the left side of the body above the kidney and is the largest lymphatic organ • The spleen filters blood, controls amount of RBC and blood storage in body, fights infection • If the spleen detects harmful agents, it will create lymphocytes • The lymphocytes will produce antibodies to kill foreign microorganisms and stop infections from spreading

Lymphatic System • Thymus is located above the heart • Small organ stores immature lymphocytes and prepares them to become active T cells which help destroy infected or cancerous cells • Tonsils are large cluster of lymphatic cells found in the pharynx • Tonsils sample bacteria and viruses entering the body through mouth and nose

Lymphatic System 3 main functions – Fluid balance-returns excess fluid and proteins from the tissues that cannot be returned through blood vessels. 2 to 3 liters is returned each day – Absorption-Absorb fats and fat soluble vitamins which contain lymph and free fatty acids. It delivers nutrients indirectly – Immune system-Defends body against unwanted organisms • Physical barriers-skin • Toxic barriers-acid from stomach • Bacteria in the body

Lymphatic System • Fight infections by producing lymphocytes. 2 types called T cells and B cells • T cells develop in thymus and once stimulated by invaders T cells produce chemicals to trigger B cells or stimulate killer T cells • B Cells produce antibodies to mark infected cells for T cells to attack and destroy • Memory B cells and memory T cells stay around to quickly identify and destroy the same invaders (pathogens)

Lymphatic System • Lymphocytes first encounter pathogens in lymph nodes where they communicate and set off defensive response • Then lymphocytes get passed in lymphatic system to reach the blood stream to fight off pathogens in the rest of the body

Reproductive System • System in males and females for the purpose of procreating • Arguably the most important system • Male reproductive system consists of the testes and penis • Major internal female reproductive system includes vagina, uterus, cervix, fallopian tubes, and ovaries

Reproductive System • Fertilization occurs if sperm enters fallopian tube and burrows into the egg • The egg then becomes implanted in the uterus with the embryo beginning to form • Then the fetus will begin to take shape • At approximately 40 weeks, the fetus is mature enough to survive outside of the womb. • The cervix will dilate and contractions of the uterus propel the baby out through the birth canal

Reproductive System • Male reproductive system produces, maintains, and transports sperm and semen • To discharge sperm within the female reproductive tract during sex • To produce and secrete male sex hormones • Most of the male reproductive system is located outside of the body

Female Reproductive System • Produces the eggs (ova) necessary for reproduction • Transports ova to site of fertilization which usually occurs in fallopian tubes • If fertilization does not occur, the system is designed to menstruate • Produces female sex hormones • External genitalia is to enable sperm to enter body and protect internal organs from infection