Anatomy & Physiology Flashcards
Explain Respiratory system
- The respiratory system, in close conjunction with the circulatory system, is responsible for supplying all body cells with essential oxygen and removing potentially harmful carbon dioxide from the body. The mouth and nose channels air from outside the body through a system of tubes of diminishing size that eventually reach the two lungs situated on either side of the heart within the chest cavity.
- We breathe in when a sheet of muscles across the bottom of the chest cavity (the diaphragm) contracts, pulling air into the lungs, and we breathe out when the diaphragm relaxes.
Air enters through the mouth and the nose, and passes through the larynx to the trachea or windpipe. This tube splits into two smaller ones called bronchi inside the chest cavity, then divides repeatedly in the lungs, connecting to millions of tiny air-filled sacs called alveoli, surrounded by tiny capillaries.
Oxygen diffuses into arterial blood through the capillary walls. Meanwhile, veins fill the alveoli with carbon dioxide waste, which flows out through the same airway when we exhale.
- Inhaled air is mostly nitrogen (about 78 percent) and about 21 percent oxygen.
Exhaled air is roughly 78 percent nitrogen, 16 percent oxygen, and 4 percent carbon dioxide.
So there is a net absorption of oxygen in the body and a net release of waste carbon dioxide.
Explain Cardiovascular/Circulatory system
- The cardiovascular/circulatory system is responsible for delivering oxygen and other nutrients to virtually all body cells and removing carbon dioxide and other waste products from them. In common with the nervous and lymphatic systems. This complex network extents into every crevice of the body.
- The heart pumps oxygen-rich blood through a network of blood vessels, the arteries. When it reaches tiny vessels called capillaries in tissues, blood releases the oxygen, which cells use to make energy.
- The cells also release waste products, such as carbon dioxide, which the blood absorbs and carries away.
The used or “deoxygenated” blood travels along veins and back to the lungs, where it absorbs fresh oxygen and begins the cycle again.
At rest, a normal heart typically beats around seventy to eighty times a minute as electrical impulses make the cardiac muscles rhythmically contract.
Each side of the heart is divided into an upper chamber called an atrium and a larger, lower chamber, called a ventricle. The atria are the blood-receiving chambers, and the ventricles are the discharging chambers. Blood flows from each atrium through a one-way valve into the ventricle below.
Explain Gastrointestinal/Digestive system
The digestive system consist of a long passageway, known as the alimentary canal or digestive tract and associated organs, including the liver, gallbladder, and pancreas.
The digestive tract starts at mouth and continues through the oesophagus and intestines to the anus.
Along its course food is broken down and nutrients extracted, while waste materials are disposed of.
- The gastrointestinal system is a chain of organs that digest food so the body can absorb nutrients. Swallowed food passes down the esophagus, which secretes mucus to help food pass easily. Then it enters the stomach, a J-shaped bag.
- Glands in the stomach lining secrete juices rich in acid and digestive enzymes, which kill some harmful bacteria and start to break food down.
- After this primary digestion, food moves into the small intestine. Here the duodenum neutralizes acidity and starts further digestion, which continues in the jejunum and ileum, coiled tubes about 13–20 ft (4–6 m) long in total.
- When digestive products reach the large intestine through the caecum, almost all nutritionally useful products have been removed. The large intestine removes water from the remains in the colon, before waste is expelled through the anus.
- The liver has many important functions, detoxifying substances like alcohol in the bloodstream and producing fat-digesting bile, which is stored in the gall bladder.
The pancreas secretes enzymes that aid digestion, as well as hormones.
Explain Skeletal system
- The skeleton makes up almost one-fifth of a healthy body weight. This flexible inner framework supports all other parts and tissues, which would collapse without skeletal reinforcement. The skeleton also protects certain organs, such as the delicate brain inside the skull. In addition, bones are reservoirs of important minerals, especially calcium, and also make new cells for the blood.
- The average skeleton has 206 bones. There are natural variations: about one individual in 20 has an extra rib. The number of small bones fused into the skull also varies.
Explain Muscular system
- Muscles are the body’s flesh. They bulge and ripple just under the skin, and are arranged in criss-crossing layers down to the bones. Their job is to contract and pull the bones to which they are anchored. Rarely working alon, they usually contract in groups, moving bones at accurate angels and by precise distances.
- Typical male body contains approximately 640 muscles, which composed around two-fifth of its weight.
What is Genome?
- A genome is the full set of genetic instructions for a living thing, controlling its development from a single cell into a complex, adult body.
- The human genome consists of an estimated 30,000-35,000 genes, carried on the double set of 46 chromosomes found in nearly every kind of body cell.
- Only 3% of human genome’s DNA is estimated to carry data to make proteins and other substances and known as “coding DNA”(genes). Some non-coding and “junk” DNA may have unknown uses, such as guiding how fast other genes make products.
Explain Urinary system
- The urinary system is composed of a pair of kidneys, a pair of ureters, a bladder, and a urethra, these components together carry out the urinary systems function of regulating the volume and composition of body fluids, removing waste products from the blood, and expelling the waste and excess water from the body in the form of urine.
- “The waste includes urea, with the chemical formula (NH2)2CO, which forms when proteins in food break down.
The main organs of the urinary system are the kidneys, which also regulate blood pressure, stabilize salt levels and produce a hormone called erythropoietin, which controls the production of red blood cells inside bone marrow.
The kidneys are a pair of purplish-brown organs just below the ribs toward the middle of the back. They remove urea from the blood through tiny filtering units called nephrons, which are balls of small blood capillaries with a small tube or “renal tubule” attached.
In the nephrons, urea, water, and other waste substances form urine that flows through tubes called ureters to the bladder, where urine is stored before excretion through the urethra.
Normal urine is sterile—it contains fluids, salts, and waste products, but no bacteria or viruses.
Explain Reproductive system in humans
- The human reproductive system consists of the organs that allow couples to produce offspring. Male sperm fertilizes a female egg, which develops into an embryo, then a full-term baby, during a gestation period of about forty weeks.
- Male testes in the scrotum produce sperm, which mature inside coiled tubules called the epididymis. During ejaculation, sperm travel up through the vas deferens, which loops around the bladder, then out through the penis, with fluids from the prostate and seminal vesicles.
- a) Semen contains nutrients for sperm and allows them to “swim” up to fertilize a woman’s egg.
- Females are born with their full complement of immature eggs—typically about two million—inside their ovaries. Within the ovary, follicles each hold one egg surrounded by cells that nourish and protect it.
- a) After puberty, hormones usually make one egg mature each month and travel to the fallopian tubes, where it might be fertilized during sex.
- b) A fertilized egg then implants itself in the uterus, which has thick muscular walls and expands as a fetus grows.
Explain Endocrine system
- The human endocrine system is a collection of glands that secrete hormones, which flow through the bloodstream and act as chemical messengers. These molecules trigger chemical changes in cells that have the appropriate receptors.
- Hormones affect certain target tissues or organs and regulate their activities.
- Hormones secreted from the pituitary gland at the base of the brain regulate a host of factors including body growth and temperature, blood pressure, sex organs in both men and women, and some aspects of pregnancy and childbirth.
- The pineal gland, also in the brain, produces melatonin, a hormone that regulates our sleep patterns.
- The thyroid gland controls how quickly the body uses energy and makes proteins.
- Two adrenal glands release the stress hormone cortisol to trigger a rise in blood glucose levels, while the pancreas secretes insulin, which regulates carbohydrate and fat metabolism.
- The endocrine system works in tandem with the nervous system, which transmits instructions round the body via networks of nerve cells.
Explain Lymph and Immune system
Several system of the body help to defend it against various hazards–such as the suns ultraviolet rays, excessive heat, harmful chemicals, physical damage, and the threat of micro organisms such as bacteria and viruses. However, the immune system, incorporating the lymphatic system, is the main means by which the body is protected from invasion.
- The immune system is a network of organs, tissues, and cells that defends the body against attacks by “foreign” bodies such as bacteria, viruses, parasites, and fungi that can cause disease. P
- a) It has an amazing ability to track down these pathogens and target them for destruction.
- The organs of the immune system include the tonsils, spleen and small bean-shaped lymph nodes laced through tiny lymphatic vessels.
- They all house lymphocytes, small white blood cells that are the immune system’s key players.
- a) Immune cells often have specialized functions—they can engulf and digest bacteria, for instance, or kill parasites.
- b) They include “killer T cells,” which mature in the thymus and attack tumors and virus-infected cells.
Some T cells “remember” past foes and quickly mount a vicious assault on subsequent encounters.
- Unfortunately, immune systems sometimes engage in friendly fire, causing diseases by destroying healthy human tissues. Other problems arise from suppressed immune systems, which can make people vulnerable to diseases such as pneumonia.
Explain Nervous system
- The nervous system is the information highway along which the brain sends instructions and receives feedback.
- a) It is made up of billions of nerve cells (neurons) that join together to make nerves, cable-like bundles wrapped in connective tissues, which transmit electrical impulses through the body.
- The central nervous system comprises the brain and spinal cord.
- An adult human brain contains about 100 billion neurons and trillions of glia, cells that carry out support functions like transporting nutrients.
- The spinal cord is a long tubular bundle of nervous tissue that runs down the vertebral column.
- The peripheral nervous system extends beyond the central nervous system. It consists of twelve pairs of cranial nerves, which emerge from the brain and mainly serve the head and neck, and thirty-one pairs of spinal nerves, which branch off from the spinal cord to the rest of the body.
- The autonomic nervous system is a part of the peripheral nervous system that controls diverse functions from heart rate to the size of our pupils, largely without conscious effort.
