An Overview of Body Systems

Systems studied in Gross Anatomy

Skeletal, Muscular, Cardiovascular, Lymphatic, Nervous, Digestive, Respiratory, Urinary, and Reproductive

Skeletal System

body's framework, composed of bones (including cartilage, ligaments, and tendons)

What does the skeletal system provide?

support, protection, and enables movement while also storing minerals and producing blood cells

The two main parts of the skeletal system

axial skeleton and appendicular skeleton

Axial skeleton

includes skull, vertebral column, ribs, and sternum - forming the central axis of the body

Appendicular skeleton

includes the bones of the limbs (arms and legs) and the girdles (pelvic and pectoral) that attach the limbs to the axial skeleton

Skeletal system main components

Bones, cartilage, ligaments, tendons, joints

Bones

206 bones in the adult human body - can be classified as different types (long, short, flat, sesamoid, and irregular) and tissues (compact or spongy bone tissue)

Cartilage

a flexible connective tissue that cushions joints and provides support in areas like the nost and ear

Ligaments

strong, fibrous tissues that connect bone to each other stabilizing joints

Tendons

strong, fibrous tissues that connect muscles to bones, enabling movement

Joints

areas where two or more bones meet allowing for different types of movements

Skin

largest organ in the body, consisting of epidermis and dermis

Epidermis

outer layer that is avascular and varies in thickness

Dermis

dense bed of connective tissue

Skin function

mechanical and permeability barrier, and as a sensory and thermoregulatory organ - initiates primary immune responses

What are the 3 main layers of the skin?

epidermis, dermis, and subcutaneous layer

Fascia

connective tissue containing varying amounts of fat that separate, support, and interconnect organs and structures, enable movement of one structure relative to another, and allow the transit of vessels and dnerves form one area to another.

What are the two categories of fascia?

deep and superficial

Superficial fasica

lies just deep to and is attached to the dermis of the skin

Deep fascia

forms a covering over deeper region of the body

What are the 3 types of muscle tissue that the Muscular System is composed of?

skeletal, smooth, and cardiac

Skeletal muscle

responsible for voluntary movements and posture

Cardiac muscles

found in the heart and is responsible for pumping blood

Smooth muscle

found in the walls of the internal organs and blood vessels, controlling involuntary movements like digestion

What do the skeletal muscles control?

voluntary movements (consciously control) like our arms and legs - attached to bones through tendons and are responsible for movement and maintaining posture

Where are the smooth muscles found?

stomach, intestines, and blood vessels - help regulate body functions

Cardiovascular system (circulatory system)

vital network responsible for transporting blood throughout the body

What does the cardiovascular system consist of?

heart, blood vessels (arteries, veins, and capillaries), and blood

The heart

acts as a pump, while the blood vessels serve as conduits for blood flow delivering oxygen and nutrients and removing waster products

4 chambers of the heart

right atrium, right ventricle, left atrium, left ventricle

3 types of blood vessels

arteries, veins, capillaries

Arteries

transports oxygenated blood AWAY from the heart to the rest of the body (with the exception of the pulmonary arteries that carry deoxygenated blood to the lungs)

Veins

transports deoxygenated blood BACK to the heart (with the exception of the pulmonary veins that carry oxygenated blood from the lungs to the heart)

Capillaries

connects the arteries and the veins and facilitates the exchange between blood and body tissues

Fluid that circulates throughout the cardiovascular system

consists of plasma and formed elements (RBCs, WBCs, and platelets)

Red blood cells (RBCs)

carry oxygen and carbon dioxide

White blood cells (WBCs)

are involved in the immune response

Platelets

help with blood clotting

How much blood does the average human contain?

5 liters (1.3 gallons of blood)

Cardio System

Lymphatic system

keep the body's fluid balance, defend the body against infection and in the absorption of fats and cell debris

What is the lymphatic system a network of?

smaller capillary - like channels that form larger vessels that ultimately connects with the large veins at the root of the neck

Nervous system function

complex communication network that can be separated into two parts based on structure or function

Structural Nervous System

CNS and PNS

Central Nervous System (CNS)

brain and spinal cord

Peripheral Nervous System (PNS)

nerves outside the CNS

Functional Nervous System

somatic and autonomic

Somatic

innervates the skin and most skeletal muscle

Autonomic

controls self-regulated action of internal organs and glands

Olfactory Cranial Nerve

sense of smell

Optic Cranial Nerve

eyes

Oculomotor Cranial Nerve

eye movement

Trochlear Cranial Nerve

eye movement

Trigeminal Cranial Nerve

sense touch, temperature, pain, CHEWING

Abducens Cranial Nerve

muscles around the eye

Facial Cranial Nerve

facial expressions

Auditory Cranial Nerve (vestibulocochlear)

hearing and balance

Glossopharyngeal cranial nerve

moves tongue, pharynx, swallowing, salivating

Vagus Cranial Nerve

Sensations of throat, larynx, thoracic, and abdominal organs

Accessory Cranial Nerve

supplies nerves to muscles of neck, trapezius, pharyngeal

Hypoglossal Cranial Nerve

movement of tongue

Ingestion

taking food into the body

Digestion

breaking down food into small molecules

Absorption

nutrients are absorbed into the bloodstream

Excretion

removal of waste products

Digestive System

consists of G.I tract and accessory organs

G.I. tract

mouth, esophagus, stomach, small intestine, large intestine

Mouth

where the food is chewed and mixed with salvia

Esophagus

muscular tube that carries food from the mouth to the stomach

Stomach

muscular organ that stores, mixes, and breaks down food with digestive juices

Large intestines

absorbs water and electrolytes, forming feces

Rectum

stores feces before elemination

Anus

the opening through which feces is expelled

Liver

produces bile which helps digest fats

Gallbladder

stores and released bile into the small intestines

Pancreas

produces enzymes that break down carbohydrates, proteins, and fats

Respiratory system

intake of oxygen and expulsion of carbon dioxide

Keys parts of respiratory system

nose, mouth pharynx (throat), larynx (voice box), trachea (windpipe), bronchi, lungs, and diaphragm

Nose and mouth

entry points for air into the respiratory system

Pharynx (throat)

passageway for both air and food connecting the nasal and oral cavities to the larynx and esophagus

Larynx (voice box)

contains the vocal cords and is involved in producing sound as well as directing air into the trachea

Trachea (windpipe)

tube that carries air from the larynx to the bronchi

Bronchi

two large tubes that branch off from the trachea each leading to a lung

Lungs

main organs for respiration where the gas exchange (oxygen and carbon dioxide) takes place in tiny air sacs called alveoli

Diaphragm

muscle below the lungs that contracts and releases to facilitate breathing

Bronchioles

smaller branches of the bronchi within the lungs that lead to the alveoli

Alveoli

tiny air sacs in the lungs where oxygen and carbon dioxide are exchanged between the air and the blood

Urinary system (renal/urinary tract)

filters waste from the blood and producing urine

What does the urinary tract consist of?

kidneys, ureters, bladder, and urethra - work together to remove waste, regulate blood volume and pressure and maintain electrolyte balance

Kidneys

two bean shaped organs located on either side of the spine, filter waste and excess water from the blood to produce urine

Ureters

tubes that carry urine from the kidneys to the bladder

Bladder

muscular sac stores urine until it is ready to be released

Urethra

tube that carries urine from the bladder to outside the body during urination

Reproductive system

collection of organs and structures responsible for producing offspring

What is the reproductive system divided into?

primary reproductive organs and secondary reproductive organs

Primary reproductive organs

gonads

Gonads

testes (males) produce sperm and testosterone and ovaries (females) produce egg/ova

Secondary reproductive organs

ducts, glands, and external genitalia

Female reproductive system includes

ovaries, fallopian tubes, uterus, vagina, and vulva