Homeostasis and Body Systems

Human Body Organization The Human Body Is composed of Organ Systems are composed of Organs Tissues Cells

Nervous System Major Structures brain, spinal cord, nerves, sense organs Functions regulates behavior; maintains homeostasis; regulates other organ systems; controls sensory and motor functions

Nerve Cells Sensory (or afferent) neurons: send information from sensory receptors (e.g., in skin, eyes, nose, tongue, ears) TOWARD central nervous system. Motor (or efferent) neurons: send information AWAY from central nervous system to muscles or glands. Interneurons: send information between sensory neurons and motor neurons. Most interneurons are located in the central nervous system.

Endocrine System Major Structures hypothalamus, pituitary, pineal, pancreas, thyroid, parathyroid, adrenal, testes, and ovaries Functions regulates body temperature, metabolism, development, and reproduction; maintains homeostasis; regulates other organ systems Interactions with other systems Nervous system and circulatory system

Circulatory System Major Structures heart, blood vessels, blood, lymph nodes and vessels, lymph , blood cells Functions transports nutrients, wastes, hormones, and gases Interactions with other systems Nervous system : The brain regulates heart rate and blood pressure. Excretory Cleans the blood Respiratory system Gas exchange in the lungs Carbon dioxide and Oxygen

Cells of the Circulatory System Red Blood Cells carry oxygen and carbon dioxide. White Blood Cells attack and destroy germs in the body. Platelets are bits of a blood cell that help stop bleeding. Plasma is the liquid part of the blood. It includes salts, waste, nutrients, water, CO2 & O2

Excretory System Major Structures kidneys, urinary bladder, ureters, urethra, skin, lungs; Nephron- filtration unit of kidney Functions removes wastes from blood; regulates concentration of body fluids Interactions Circulatory system Endocrine system

Respiratory System Major Structures Nose, mouth, voice box (larynx), trachea, bronchi, lungs, alveoli (air sacs) Functions moves air into and out of lungs; controls gas exchange between blood and lungs Interactions: Circulatory system Nervous system

Pathway: nose->pharynx->larynx-> trachea->bronchi-> Lungs-> bronchioles ->alveoli

Muscular System Major Structures skeletal, smooth, and cardiac muscle tissues Functions moves limbs and trunk; moves substances through body; provides structure and support Interactions with other systems Skeletal system - provide skeletal movement Digestive system- controls entrances and exits of digestive tract Endocrine system- shiver to produce heat Nervous system – helps sense of balance, pressure Respiratory system- makes diaphragm contract & relax Cardiovascular system – heart pumps to provide circulation

Types of Muscle Cells Cardiac Muscle cells - are branched and striped Skeletal Muscle cells - are striped and have many nuclei Smooth muscles- are pointed at both ends

Skeletal System Major Structures Bones, joints and Bone marrow Functions protects and supports body and organs; interacts with skeletal muscles; produces red blood cells, white blood cells, and platelets Interactions with other systems Nervous System Bones provide calcium needed for proper functioning of nerve cells Circulatory system Skeletal system protects internal organs and produces blood cells.

Cells of the Skeletal System Cells in the Bone that work with the Circulatory System

Integumentary System Major Structures skin, nails, hair, fat, nerves and blood vessels Functions protects against injury, infection, production of Vitamin D, and fluid loss; helps regulate body temperature Interactions with other systems Immune system First line of defense against infection Nervous system Complex network of nerves in skin send and receive impulses to and from brain, creating sense of touch. Sense heat, cold, pain, pressure & touch

Cells of the Integumentary Melanocyte- makes pigment (melanin) Langerhans' cell- frontline defense for the immune system in skin Adipose (fat) cells- provide insulation from heat and cold

Digestive System Major Structures mouth, throat, esophagus, stomach, liver, pancreas, small and large intestines Functions extracts and absorbs nutrients from food; removes wastes; maintains water and chemical balances Interactions with other systems Integumentary system vitamin D activated in skin helps the absorption of calcium from digestive tract. Reproduction system, Adequate nutrients, including fats, are essential for conception and normal development. Sequence of food pathway through system Mouth, esophagus, stomach, small intestine and large intestine.

What Benefits Do Gut Bacteria Provide? Digestive System What Benefits Do Gut Bacteria Provide? Bacteria produce enzymes that digest polysaccharides in plant cell walls. Plants contribute to fiber in our diet for a healthy colon, but the enzymes released by good bacteria let us get the most nutrition from vegetables Some digestive system bacteria make vitamin K and B group vitamins – (difficult to get from food) Humans can’t make these. Bacteria help maintain an optimum pH and stimulate the immune system. Gut bacteria breakdown drugs, hormones and cancer-causing environmental substances Bacteria in the human gut are beneficial to their host, and enjoy a safe environment . What type of symbiotic relationship is this an example of ? MUTUALISM

Immune System Major Structures white blood cells, lymph nodes and vessels, skin, spleen Functions defends against pathogens and diseases Interactions Circulatory- delivers WBC’s where needed Skeletal- makes WBC’s in red bone marrow

Cells of the immune system

What happens: B cells recognize pathogens by the proteins (antigens) on their surface. Helper T cells activate the B cells. B cells divide to make plasma and memory B cells. Plasma B cells produce antibodies that attach to the pathogen marking it for destruction. Macrophages see the antibodies and eat pathogen cells Memory cells are stored in the lymph nodes. They give a rapid immune response the next time the pathogen attacks.

Reproductive System Major Structures ovaries, fallopian tubes, uterus, and breasts (in females); testes and penis (in males) Functions The male and female gonads (testes and ovaries) produce sex cells (ova and sperm) and the hormones necessary for the proper development, maintenance, and production of gametes and offspring

Gametes of the Reproduction system Egg Sperm Gametes of the Reproduction system