anatomy

Anatomical Regions

Anatomical Regions

Divisions of the body used to describe the location of structures.

Anatomy

The study of structures in the body, such as cells and organs.

Physiology

The study of the function of bodily structures.

Nervous System

Controls and coordinates body activities, processes sensory information, and enables communication between different parts of the body.

Muscular System

Allows movement, provides support and posture, generates heat.

Skeletal System

Provides structural support, protects internal organs, facilitates movement, stores minerals, and produces blood cells.

Circulatory System (Cardiovascular System)

Transports oxygen, nutrients, hormones, and waste products throughout the body; helps regulate body temperature.

Respiratory System

Facilitates the exchange of gases between the body and the environment; helps regulate pH.

Digestive System

Breaks down and absorbs nutrients from food; eliminates waste.

Excretory System (Urinary System)

Filters and eliminates waste products from the blood; regulates electrolyte and fluid balance.

Endocrine System

Produces and secretes hormones that regulate various body functions.

Reproductive System

Facilitates reproduction and the continuation of the species.

Integumentary System (Skin)

Protects against physical injury, pathogens, and dehydration; helps regulate body temperature; houses sensory receptors.

Immune System

Defends the body against pathogens and eliminates abnormal cells.

Lymphatic System

Maintains fluid balance, transports fats, and supports the immune system.

Elements of a control system

Receptor, Afferent pathway, Control center, Efferent pathway, Effector.

Negative feedback

Effects of a reaction slow or stop the reaction.

Positive feedback

Amplifies the difference between the reference input/output.

Anatomical position

Standing upright, facing forward, palms facing forward.

Anterior

Front of the body.

Posterior

Back of the body.

Superior

Above.

Inferior

Below.

Medial

Midline of the body.

Lateral

Away from the midline.

Proximal

Close to the point of attachment.

Distal

Far from the point of attachment.

Superficial

Shallow.

Deep

Internal.

Sagittal section

Split into left and right parts.

Median/Midsagittal

Equal left and right parts.

Frontal/Coronal

Anterior and posterior parts.

Transverse

Superior and inferior parts.

Dorsal body cavity

Back of the body, head, and back of the trunk.

Cranial cavity

Contains the brain and is protected by the skull.

Spinal cavity

Contains the spinal cord and is protected by the vertebrae.

Ventral body cavity

Thoracic cavity and abdominopelvic cavity.

Acids

Substances with a pH less than 7.

Bases

Substances with a pH greater than 7.

Inorganic compounds

Substances where two or more chemical elements (other than carbon) are combined.

Water

An example of an inorganic compound.

ATP

Adenosine triphosphate, consists of a sugar molecule, nitrogenous base, and chain of three phosphate groups.

Cell junctions

Specialized structures that connect cells together in tissues.

Tight junctions

Seal the space between cells, preventing substances from leaking between cells.

Adherens junctions

Help cells adhere to each other and provide mechanical strength to tissues.

Desmosomes

Spot welds that hold cells together, found in tissues that experience mechanical stress.

Gap junctions

Allow direct communication between cells, allowing small molecules and ions to pass through.

Epithelial tissues

Sheets of cells that cover body surfaces and line body cavities.

Simple squamous epithelium

Single layer of flat scale-like cells, found in areas where diffusion and filtration occur.

Stratified squamous epithelium

Multiple layers of flat cells, provides protection against mechanical stress.

Simple cuboidal epithelium

Single layer of cube-shaped cells, involved in secretion and absorption.

Simple columnar epithelium

Single layer of tall, column-shaped cells, involved in absorption and secretion.

Pseudostratified columnar epithelium

Single layer of cells of varying heights, found in the respiratory tract.

Exocrine glands

Secrete products into ducts, which carry substances to a specific location on the body's surface or a body cavity.

Endocrine glands

Release secretions, or hormones, directly into the bloodstream.

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Axial skeleton

The axial skeleton includes the bones of the skull, vertebral column, and rib cage. It provides support and protection for the central nervous system and vital organs.

Appendicular skeleton

The appendicular skeleton includes the bones of the upper and lower limbs, as well as the shoulder and pelvic girdles. It is involved in movement and locomotion.

Skull

The skull is composed of several bones, including the cranium and facial bones. It protects the brain and houses the sensory organs.

Vertebral column

The vertebral column, also known as the spine or backbone, is made up of individual vertebrae. It provides support, flexibility, and protection for the spinal cord.

Rib cage

The rib cage consists of the ribs, sternum, and thoracic vertebrae. It protects the heart, lungs, and other organs in the thoracic cavity.

Upper limb bones

The upper limb bones include the humerus, radius, ulna, carpals, metacarpals, and phalanges. They are involved in arm and hand movements.

Lower limb bones

The lower limb bones include the femur, tibia, fibula, tarsals, metatarsals, and phalanges. They are involved in leg and foot movements.

Shoulder girdle

The shoulder girdle consists of the clavicle and scapula. It connects the upper limb to the axial skeleton and allows for arm movement.

Pelvic girdle

The pelvic girdle consists of the hip bones (ilium, ischium, and pubis). It supports the weight of the upper body and protects the pelvic organs.

Sternum

The sternum, also known as the breastbone, is located in the center of the chest. It provides attachment points for the ribs and protects the heart and lungs.

Phalanges

Phalanges are the bones of the fingers and toes. They allow for fine motor movements and provide support for grasping and walking.

Carpals

Carpals are the bones of the wrist. They provide stability and flexibility to the hand.

Tarsals

Tarsals are the bones of the ankle. They provide support and stability to the foot.

Metacarpals

Metacarpals are the bones of the palm. They connect the carpals to the phalanges.

Metatarsals

Metatarsals are the bones of the foot. They connect the tarsals to the phalanges.

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The neuromuscular junction is the point of communication between a motor neuron and a muscle fiber. It consists of three main components:the motor neuron terminal, the synaptic cleft, and the motor end plate.

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The motor neuron terminal is the end of the motor neuron that is in close proximity to the muscle fiber. It contains vesicles filled with a neurotransmitter called acetylcholine.

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The synaptic cleft is the small gap between the motor neuron terminal and the motor end plate of the muscle fiber. It acts as a barrier that the acetylcholine must cross to transmit the signal from the motor neuron to the muscle fiber.

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The motor end plate is a specialized region on the surface of the muscle fiber that contains receptors for acetylcholine. These receptors are called nicotinic acetylcholine receptors.

The acetylcholine molecules then diffuse across the synaptic cleft and bind to the nicotinic acetylcholine receptors on the motor end plate.

This action potential then propagates along the muscle fiber, resulting in muscle contraction.

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Neuromuscular junction

The point where a motor neuron and a muscle fiber meet, allowing communication between the nervous system and the muscular system.

Synaptic cleft

The tiny gap between the motor neuron and the muscle fiber, where acetylcholine is released and diffuses across to bind to receptors on the muscle fiber.

Acetylcholine

A chemical released into the synaptic cleft that triggers muscle contraction by binding to receptors on the muscle fiber.

Agonist muscles

Muscles primarily responsible for producing a specific movement by contracting and generating force.

Antagonist muscles

Muscles that work in opposition to the agonist muscles by relaxing and lengthening to allow smooth movement.

Synergist muscles

Muscles that assist the agonist muscles in performing a movement by stabilizing the joint or assisting in the action.

Flexion

The movement of bending or decreasing the angle between two body parts, performed by muscles like the biceps brachii and hamstrings.

Extension

The movement of straightening or increasing the angle between two body parts, performed by muscles like the triceps brachii and quadriceps.

Abduction

The movement of moving a body part away from the midline of the body, performed by muscles like the deltoids and gluteus medius.

Adduction

The movement of moving a body part toward the midline of the body, performed by muscles like the adductor muscles and pectoralis major.

Rotation

The movement of turning or twisting a body part around its axis, performed by muscles like the external obliques and rotator cuff muscles.

Myofibrils

Smaller units within muscle fibers that are made up of repeating units called sarcomeres, which are the functional units of muscle contraction.

Sarcomeres

The functional units of muscle contraction, composed of thick myosin filaments and thin actin filaments arranged in a highly organized pattern.

Sliding filament theory

The theory that explains muscle contraction by the interaction of myosin heads on thick filaments with actin filaments, causing them to slide past each other and leading to muscle shortening.

Neurotransmitters

Messengers that transmit signals between nerve cells, released into the synapse and bind to receptors on the receiving neuron to transmit the signal.

Acetylcholine (ACh)

The neurotransmitter responsible for initiating muscle contractions by binding to receptors on the muscle cell membrane.

Creatine phosphate

A molecule that stores high-energy phosphate groups and donates them to ADP to regenerate ATP, the primary energy source for muscle contractions.

Muscle fatigue

The occurrence of muscle fatigue due to depletion of energy sources like ATP, accumulation of metabolic byproducts, impaired muscle function, and electrolyte imbalance.

Isometric contraction

Muscle contraction without a change in the length of the muscle, used for maintaining posture and stability.

Isotonic contraction

Muscle contraction with a change in the length of the muscle, used for movements like walking, running, and lifting.

Atrophy

The shrinking or decrease in size of a muscle or tissue due to disuse, aging, or medical conditions.