Comprehensive Human Body Systems: Anatomy, Functions, and Interactions

Nasal Cavity

Air is warmed, humidified, and filtered by mucus and hair.

Pharynx

Junction for both food and air.

Larynx

Voice box.

Trachea

Cylinder tube with rings of cartilage that provides support.

Right lung

Has 3 lobes.

Left lung

Has 2 lobes.

Alveoli

Tiny air sacs of the lungs that allow gas exchange.

Conducting zone

Transports air from the outside environment to the site of gas exchange; also called the 'anatomical dead space.'

Respiratory zone

Structures in lungs where gas exchange takes place.

Peristalsis

Muscle contractions that move food through the digestive tract.

Central nervous system

Consists of the brain and spinal cord; acts as the command center for all communication and actions of the body.

Peripheral Nervous system

Consists of all nerves and ganglia that branch from the brain and spinal cord.

Nerves

Long bundles of neuronal axons that transmit signals from the central nervous system.

Synapse

A structure that allows neurons to pass signals to other neurons, muscles, or glands.

Dendrite

A nerve fiber that carries a nerve impulse towards the neuron cell body.

Sensory neurons

Send messages to CNS about sensory info like touch, smell, and pain.

Motor neurons

Send messages to muscle and can be subdivided into involuntary motor nervous system and the somatic voluntary nervous system.

Autonomic nervous system

Controls involuntary actions involving cardiac and smooth muscle.

Somatic nervous system

Controls voluntary actions involving skeletal muscle.

Muscular system

Vital for controlling involuntary and voluntary movement.

Tissues

A group of cells with similar structures that function together.

Skeletal muscles

Attach to the bone, involved with movement of bones, striated and strong, and is the only voluntary muscle tissue in the body.

Cardiac muscle

At the heart, striated, and involuntary.

Smooth muscle

Found in walls of hollow organs, weakest muscle, and involuntary.

Tendons

Tough bands of connective tissue that have strong collagen fibers.

Myofibrils

Long strands of proteins made of sarcomere units.

Sarcomere

The contracting unit of a muscle.

Myosin

Thick filaments that can split ATP and react to actin in muscle contraction.

Actin

Thin filaments that form the contractile filaments of muscle cells.

Afferent nerves

Carry sensory information to the brain.

Efferent nerves

Carry signals from the brain to muscles.

Extensibility

Ability of muscles to be stretched or extended.

Elasticity

Ability of muscle to return to original length when relaxed.

Excitability

Ability of muscle to respond to a stimulus from a motor neuron or hormone.

Contractility

Ability of muscle to shrink or contract.

Reproductive system

Purpose is to generate gametes and deliver them to the female reproductive system.

Vas deferens

Duct in which sperm moves from testicle to urethra.

Seminiferous tubules

Where sperm is produced in testes.

Fallopian tubes

Connect the ovaries to the uterus.

Zygote

A fertilized egg.

Implantation

Process by which a blastocyst implants itself in the uterine wall.

Hormones

Part of the endocrine system that allows for cell-to-cell communication.

Follicle-stimulating hormone (FSH)

Hormone secreted by the anterior pituitary that stimulates development of eggs in ovaries and sperm in testes.

Luteinizing hormone (LH)

Hormone secreted by the anterior pituitary that is responsible for triggering ovulation in ovaries and production of testosterone by testes.

Corpus luteum

The empty mature follicle that produces large amounts of progesterone to prepare the endometrium for implantation of the fertilized egg.

Menstrual cycle

The cycle of maturation and shedding of the endometrium.

Testes

Male reproductive organs that produce sperm.

Ovaries

Female reproductive organs that produce eggs.

Integumentary system

Largest organ, the skin, containing organs and glands vital to protecting the body and regulating temperature.

Sebaceous glands

Accessory structures originating in the dermis that secrete sebum onto hair emerging from the hair follicle.

Ceruminous glands

Accessory structures that produce ear wax.

Epidermis

The outermost layer of skin made up of dead cells on the outside and an inner layer of living cells.

Dermis

The middle layer of skin that contains collagen, blood vessels, glands, hair follicles, and nerve endings.

Hypodermis

The innermost layer of skin.

Melanocytes

Cells in the epidermis that produce and distribute melanin, which is a skin pigment.

Homeostasis

The maintenance of stable internal conditions in the body.

Negative feedback

A mechanism that includes monitoring for specific homeostatic levels and a signal to a gland to maintain homeostasis.

Thyroid gland

Gland in the neck that secretes hormones that regulate growth, development, and metabolic rate.

Parathyroid gland

Gland in the neck that produces parathyroid hormone.

Thymus

Lymphoid organ that produces T cells.

Adrenal gland

Gland above the kidney that produces hormones to regulate heart rate, blood pressure, and other functions.

Pancreas

Gland of digestive and endocrine systems that produces insulin and secretes pancreatic juices.

Pineal gland

Small gland near the center of the brain that secretes melatonin.

Sperm

Male gametes produced by the testes.

Eggs

Female gametes produced by the ovaries.

Sweat glands

Glands that produce sweat to help cool the body.

Vitamin D

Produced by the skin when ultraviolet light hits it.

Collagen

A protein found in the dermis that provides structure and support to the skin.

Blood vessels

Structures in the dermis that supply blood to the skin.

Apocrine sweat glands

Sweat glands found in the skin that are associated with hair follicles.

Eccrine sweat glands

Sweat glands that are distributed throughout the skin and help regulate body temperature.

Monomers

The monomers used to build polysaccharides.

Polysaccharides

Molecules made of two or a few monosaccharide units that are used for fuel in the body.

Endocrine glands

Glands that produce hormones with different chemical structures.

Lipid-based hormones

Hormones that can enter a cell and regulate DNA.

Epinephrine

A polar, water-soluble hormone released in response to stress.

Fight-or-flight response

The response caused by the secretion of epinephrine into the bloodstream.

Hyperthyroidism

A condition where the thyroid gland releases too much thyroxine.

Gigantism

Occurs when the pituitary gland makes too much growth hormone, causing excessive growth.

Antidiuretic hormone (ADH)

Hormone secreted by the pituitary gland that helps maintain the right amount of water in the blood.

Positive feedback

Causes an increase in the secretion of a hormone.

Oxytocin

Hormone that stimulates uterine contractions during childbirth.

Insulin

Hormone released by the pancreas that lowers blood sugar levels.

Glucagon

Hormone that promotes the breakdown of glycogen into glucose, raising blood sugar levels.

Neuroendocrine system

The integration of the nervous and endocrine systems.

Releasing hormones

Hormones secreted by the hypothalamus that stimulate the pituitary gland.

Inhibiting hormones

Hormones that turn off messages to the pituitary gland.

Urinary system

System that functions in the excretory process.

Kidneys

Organs that filter blood and produce urine.

Renal cortex

The outer layer of the kidney where blood vessels are located.

Renal medulla

The inner region of the kidney where the concentration of urine is regulated.

Urinary bladder

Organ that stores urine until it is excreted.

Ureters

Small tubes that carry urine from the kidneys to the urinary bladder.

Urethra

Tube through which urine is excreted from the body.

Nitrogenous waste

Toxic byproduct from protein digestion that must be removed from the body.

Erythropoietin

Hormone produced in the renal cortex that stimulates the production of new red blood cells.

Acromegaly

Condition caused by too much growth hormone in adults.

Nephron

The structural and functional unit of the kidney.

Glomerulus

A small, dense group of capillaries in the nephron where material is filtered from the blood.

Filtrate

Material filtered from the blood, including water, urea, glucose, salts, and other small molecules.