Human Anatomy and Body Systems

Levels of Organization Remember, the human body is organized in several levels, from the simplest to the most complex... Cells – the basic unit of life Tissues – clusters of cells performing a similar function Organs – made of tissues that perform one specific function Organ Systems – groups of organs that perform a specific purpose in the human body ***The purpose of the 11 organ systems is for the human body to maintain homeostasis.

The 11 Human Body Systems The 11 human body systems are as follows: -- nervous system-- integumentary system -- respiratory system-- digestive system -- excretory system-- skeletal system -- muscular system-- circulatory system -- endocrine system-- reproductive system -- lymphatic (immune) system

The Digestive System Function: to convert food particles into simple molecules that can be absorbed into the blood and used by the body Major Organs and their Functions: Mouth – to chew and grind up food (mechanical) -- amylase in the saliva begins the chemical breakdown Esophagus – pipe connecting mouth to stomach Stomach – secretes pepsin, an enzyme that breaks down food. The stomach has a pH of 2.

Small Intestine – after digestion is complete, the chyme (processed stomach contents) enters the small intestine where it is absorbed into the bloodstream by the help of small hairs called villi.

Large Intestine – removes water from the chyme and gets the waste ready for excretion The nutrients that are absorbed during digestion travel into the Circulatory System to be distributed through the body!

Liver – produces bile, which breaks down fats in foods. This is an accessory organ. Gallbladder – pouch-like organ that stores bile for future use

The Digestive System

Explain how the Digestive system works closely with the: Circulatory system Muscular system Endocrine system

The Excretory System Kidneys-Ureter-Bladder-Urethra Function: to rid the body of wastes, including excess water and salts

Major Organs of excretion Kidneys – the main organ of the excretory system; excretion begins here -- Kidneys filter the blood, removing wastes

More excretory organs : Skin – sweat glands remove excess water and salts from the body Lungs – expel the waste product carbon dioxide (cellular respiration) Question: Can one organ be part of TWO systems?

Explain how the excretory system works closely with the: Circulatory system Integumentary system Homeostasis

The Nervous System Function: to coordinate the body’s response to changes in its internal and external environment The basic unit of structure in the nervous system is the neuron (nerve cell)

Major Organs of the Central Nervous System Brain – control center of the body Divided into 2 halves Controls conscious activities, intelligence, memory, language, muscle movement, senses

Brain stem controls breathing and heart rate Medulla oblongata reacts to increased CO2 levels to increase rate of breathing

Spinal Cord – sends instructions from the brain to the rest of the body and vice versa -- any organism with a major nerve cord is classified as a chordate Nerves – conduct impulses to muscle cells throughout the body

Explain how the nervous system works closely with the: Integumentary system Muscular system Endocrine system

Which 2 body systems are working together in this image?

The Circulatory System Function: to deliver oxygen to the body and brain; to deliver nutrients from the digestive system.

Image of the Circulatory System

Heart – the major muscle of the circulatory system pumps blood through its four chambers (two ventricles and two atria) pumps deoxygenated blood into the lungs, where it gets oxygenated, returns it to the heart, and then pumps out through the aorta to the rest of the body valves regulate the flow of blood between the chambers

Arteries – carry blood away from the heart and to the major organs of the body Veins – carry blood back to the heart away from the major organs of the body Capillaries – small blood vessels (one cell thick) where gas exchange occurs, connects arteries and veins

Red Blood Cells: contain hemoglobin; carries oxygen throughout body White Blood Cells: fight disease Platelets: fragments that help blood clot Plasma: liquid part of the blood

Explain how the circulatory system works closely with the: Respiratory system Digestive system Endocrine system

The Respiratory System Function: to provide the body with a fresh supply of oxygen for cellular respiration and remove the waste product carbon dioxide

Major Organs Nose – internal entry and exit point for air Trachea – the “windpipe” Bronchial Tubes – the two large passageways that lead from the trachea to your lungs (one for each lung) Alveoli – clusters of tiny sacs where gases are exchanged with the bloodstream.

Diaphragm - the muscle that causes you to breath Cilia – tiny hairs that line the air passages that trap tiny particles

The respiratory system and circulatory system work closely together:

Explain how the respiratory system works closely with the: Circulatory system Muscular system Endocrine system

The Muscular System Function: works with the skeletal and nervous system to produce movement, also helps to circulate blood through the human body

Muscle contractions can be: Voluntary: skeletal muscles Involuntary: smooth (intestinal) muscles, cardiac muscle Major Skeletal Muscles -- biceps (flexor)-- triceps (extend) -- deltoids-- rectus abdominus -- gluteus maximus-- hamstrings

Over 600 muscles in your body Control movement Voluntary: you choose to move them Involuntary: controlled unconsciously by the brain Which muscle would raise this arm? Straighten the arm?

Explain how the muscular system works closely with the: Circulatory system Skeletal system Nervous system

Integumentary System Comprised of the largest organ in the body which is our skin. Hair and nails are also in this system. Functions: Skin is our first line of defense against disease. It also helps regulate body temperature, excretes wastes through sweating, and maintains homeostasis in a variety of ways.

Examples of human HOMEOSTASIS: 1.Sweating 2.Shivering 3.Thirst 4.Increased/decreased breathing 5.Increased/decreased heart rate Integumentary

Explain how the integumentary system works closely with the: Circulatory system Nervous system Excretory system

The Skeletal System Function: to provide structure and support to the human body Bones are where new blood cells are generated (in the marrow), and require the mineral calcium for strength Major Bones of the Human Body -- femur (thigh bone)-- humerus (upper arm) -- radius and ulna (lower arm)-- cranium (skull) -- sternum (breastbone)-- clavicle (shoulder blade) -- fibula and tibia (calf)-- vertebrae (back) -- scalpula (shoulder)-- pelvic bone

Axial Skeleton: (white) skull, ribs, spine Appendicular Skeleton: (purple) arms, legs, pelvis

Bones are living tissue There are 206 bones in the human body The skeletal system works closely with the muscular system (the muscles move the bones)

Explain how the skeletal system works closely with the: Respiratory system Muscular system Endocrine system

The Lymphatic (Immune) System Function: to remove infectious diseases and other pathogens from the human body The lymphatic system transports tissue fluid (called lymph) and filters out disease-causing pathogens (through lymph nodes)

Major Organs Skin –the body ’ s first line of defense Tonsils – trap bacteria that enter mouth/nose Lymph Nodes – help restore fluid lost by the blood and return it to the circulatory system Spleen – filters out and destroys bacteria and worn out blood cells

White Blood Cells – recognize pathogens and create antibodies to tag and remove these HIV attacks helper T cells (a type of white blood cell)

Explain how the lymphatic system works closely with the: Circulatory system Integumentary system Skeletal system

Reproductive System Function: The reproductive system helps humans reproduce and ensures the survival of the species.

The primary female reproductive organs are the ovaries, and the primary male reproductive organs are the testes. Ovaries produce the female hormones estrogen and progesterone and the testes produce testosterone.

Through meiosis, the female (eggs) and male (sperm) gametes are produced. They have HALF the number of chromosomes as other cells (haploid). When an egg and sperm fuse, fertilization takes place and a zygote is formed. It develops into an embryo which becomes a baby. Sperm cells have flagella for movement

. Each month, an egg is released by one of the 2 ovaries. If fertilization occurs, it will occur in the oviduct. The fertilized egg (zygote) travels to the uterus and implants into the uterine wall. The fetus will develop in the uterus for 9 months.

If a human body cell has 46 chromosomes, how many chromosomes does each gamete have after meiosis?

Explain how the reproductive system works closely with the: Endocrine system Muscular system Nervous system

The Endocrine System Function: to control growth, development, metabolism and reproduction through the production and secretion of hormones

Major Organs Pancreas: secretes insulin which regulates blood sugar Pituitary gland (brain): secretes growth hormone Thyroid: regulates metabolism Adrenal Glands: prepare body for fight or flight Testes & Ovaries: produce sex hormones

Explain how the endocrine system works closely with the: Circulatory system Nervous system Respiratory system

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