Important Terminology

• Inferior - below or further away from the head

• Superior - above or nearer to the head 

• Proximal - nearer to where a limb attaches to the body

• Distal - further away from where a limb attaches to the body 

• Posterior – behind or nearer to the back 

• Anterior - the front or nearer to the front 

• Internal - located inside or further away from the surface 

• External - located on or near the surface 

• Lateral - further away from the midline of the body 

• Medial - closer to the midline of the body
  

Skeletal System

Axial Skeleton (80 bones)

• Skull

  • Protects the brain, forms the orbit of the eyes, attachment to muscles, and structure to the face.

•  Ribs/Thoracic Cage

  • Protects and supports the internal organs of the body such as the heart and lungs and some of the abdominal organs like kidneys and liver.

    • 12 pairs of ribs

      • 1-7 → true ribs

        • Directly attached to the sternum

      • 8-10 → false ribs

        • Indirectly attached to sternum

      • 11-12 → floating ribs

        • Not attached to the sternum

• Sternum

  • A flat bone that starts at the bottom of the throat and runs to about halfway down the centre of the chest.

• Vertebral Column (33)

  • Supports the spinal cord and supports the head. It provides articulation sites for ribs and innominate bones of the pelvic girdle. It is also responsible for the flexibility of the back.

    • Cervical Vertebrae (7)

      • Smallest vertebrae

      

      • More movement than thoracic and lumbar vertebrae

    • Thoracic Vertebrae (12)

      • Restricts movement

        • Ribs are attached to the side of each vertebrae

    • Lumbar Vertebrae (5)

      • The biggest and strongest of the vertebrae

        • Plays a major role in weight-bearing

    • Sacral Vertebrae (5)

      • Transmits weight from body to pelvis and legs

    • Coccygeal Vertebrae (4)

      • The bone at the end of the spinal column that is composed of four vertebrae combined into one bone

Appendicular Skeleton (126 bones)

• Pectoral (Shoulder) Girdle

  • Functions to anchor and support the upper limbs serve as an important attachment site for many muscles that help to move the arms.

• Pelvic (Hip) Girdle 

  • Supports and protects the soft vital organs of the abdominal cavity, transfers the weight of the upper axial skeleton to lower appendicular parts, especially during body movement, and provides attachment to the lower limbs.

• Upper Extremity/Arms (humerus, ulna, radius, carpal bones, metacarpals, and phalanges)

  • Helps in the hand movement to perform various activities, and helps the shoulder to perform a wide range of motions.

• Lower Extremity/Legs (femur, tibia, fibula, tarsal bones, metatarsals, and phalanges)

  • Weight-bearing bones that support the entire structure of the body while walking, jumping, or running.

Types of Bones:

• Long bones usually have a long cylindrical shaft and are enlarged at both ends; can be large or small, but the length is always greater than the width; most important bones for movement.

  • They include the femur, metatarsals, and clavicle

• Short bones are small and cube-shaped, and they usually articulate with more than one other bone. 

  • Short bones include the carpals of the hand and tarsals of the foot. 

• Flat bones usually have curved surfaces and vary from being quite thick to very thin; provide protection, and the broad surfaces also provide a large area for muscle attachment.

  •  Flat bones include the sternum, scapula, ribs, and pelvis

• Irregular bones have specialized shapes and functions.

  • Irregular bones include the vertebrae, sacrum, and coccyx.

Parts of Long Bone

• Epiphysis: Two end partitions of a long bone, each covered by articular cartilage.

• Diaphysis: Compact part of a long bone; a long shaft covered by a periosteum membrane. Important for protection.

• Periosteum: Membrane of a long bone for protection.

• Spongy Bone: A type of bone tissue found at the ends of long bones and in the middle of other bones such as the vertebrae. It is lighter and less dense than compact bone; and contains red bone marrow, which is responsible for producing blood cells.

• Articular Cartilage: Smooth, white tissue that covers the ends of bones where they come together to form joints, helps to reduce friction, and absorbs shock.

• Bone Marrow:  Soft fatty substance in the cavities of bones, in which blood cells are produced; RED → produces blood cells and platelets. Yellow marrow → stores fat

• Compact Bone: The external layer of the bone that is very dense, filled with passageways for nerves, blood vessels, and the lymphatic system.

• Marrow Cavity: Space within the diaphysis where yellow marrow is stored for white cell production.

Connective Tissue

• Functions:

  • to join bodily structures like bones and muscles to one another or hold tissues like muscles, tendons, or even organs in their proper place in the body.

  • gives reinforcement to joints, strengthening and supporting the articulations between bones.

  • transports nutrients and metabolic by-products between the bloodstream and the tissues to which it adheres.

• Structure: 

  • made up of proteins like collagen, elastin, and intercellular fluid.

  • the form can range from a thin sheet to a dense rope of fibers.

Joints

• Also known as an articulation; where two or more bones come into contact or articulate with each other.

• Different Types of Joints

  • Fixed Joints 

    • Very stable, with no observable movement, bones are joined by strong fibers called sutures.

  • Cartilaginous Joints

    • Allows slight movement, the ends of the joint are covered with white pads of fibrocartilage, which act as shock absorbers.

  • Synovial Joints 

    • The most common type of joint that allows a wide range of movement and is subdivided according to movement possibilities, is characterized by the presence of a joint capsule and cavity lined with a synovial membrane.

• Synovial Joints

  • Features

    • Ligament

      • Structure: A band of strong fibrous connective material.

      • Function: Joins bone to bone, and provides stability.

    • Pads of fat 

      • Found between capsule, bone, or muscle.

      • Increases joint stability, acts as a shock absorber, and reduces friction.

    • Meniscus Tough

      • Flexible discs of fibrocartilage.

      • Improves fit between the bone ends, increases stability, and reduces wear and tear to joint surfaces.

    • Bursae Fluid 

      • A filled sac is found between the tendon and bone.

      • Reduces friction, found in body areas of high stress.

    •  Articular Cartilage 

      • Smooth and spongy covers of the end of bones

      • Prevents friction between articulating bones

    • Synovial Fluid 

      • Slippery fluid that fills the joint capsule.

      • Reduce friction, nourish cartilage, and get rid of waste from the joint.

    • Layered Joint Cavity 

      • Outer layer – tough and fibrous

      • Inner layer – synovial membrane covers all internal surfaces

      • Strengthen joint, secrete synovial fluid

  • Types

    • Gliding

      • Usually flat or slightly curved, slide across each other, with the least amount of movement.

    • Hinge

      • The articular surfaces have been fused so movement in one direction, joined by ligaments, movement is only allowed in one plane (extension/flexion).

    • Pivot

      • The rounded surface of one bone that rolls around a ring formed by bone and ligament.

    • Condyloid

      • A ball-shaped bone that fits into a cup.

    • Saddle

      • Saddle-shaped bone that fits into a bone shaped like the legs, and can move up, down, side to side.

    • Ball and Socket

      • A sphere-shaped bone that fits into a rounded cavity, covered in cartilage to prevent friction and a high range of movements.

Muscular System

Origin: the attachment of a muscle tendon to a stationary bone, usually the most proximal attachment Insertion: the attachment of a muscle tendon to a moveable, usually the most distal attachment

Characteristics:

• Contractility: The ability of the muscle to contract and generate a force when it is stimulated by a nerve

• Extensibility: The ability to extend before its normal resting state.

• Elasticity: The muscle's ability to return to its original resting length.

• Atrophy: Muscle wastage, lack of physical activity, poor nutrition, and disease.

• Hypertrophy: Growth and increase in the size of the muscle, most commonly as a result of weight training.

• Nerve Stimuli: A nerve that sends a signal for the muscle to contract.

• Fed by capillaries: Gaseous exchange that occurs in the capillaries so oxygen can be delivered to the muscles.

Types of Muscles:

• Skeletal muscle: Under voluntary control, has a striated appearance, has tendons that attach the muscle to the bone, and the main function is to move the skeleton.

• Cardiac muscle: Under involuntary control, striated, heart muscle.

• Smooth muscle: Lines the walls of the blood vessels and hollow organs such as the stomach or intestines, involuntary control, not striated.

Integumentary System

Functions:

• Regulation of Body Temperature: if it is cold, hairs on the skin will stand up and blood flow in the capillaries is decreased.

  • If it is warm, hair muscle relaxes so heat can escape; Also, sweat is secreted which cools us down. 

• Protection and Immunity: The skins form a physical barrier through specialized cells of the immune system.

  • These cells detect bacteria and viruses, and they are called antibodies.

• Sensation: Sensation is a feeling that is localized on the skin’s surface.

  • They are processed through receptors in the dermis.

• Excretion: Sweat glands remove waste such as urea, uric acid, and ammonia and help regulate body temperature when overheating.

• Synthesis of Vitamin D: From the sunlight, we need vitamin D to aid with calcium, iron, magnesium phosphate, and zinc absorption through the liver and kidney.

  • The epidermal cells convert ultraviolet rays into vitamin D.

Nervous System

Functions of Parts of the Brain:

• Brain Stem

  • Location: Posterior part of the brain linking to the top of the spinal cord.

  • Control center for the regulation of cardiac and respiratory function, consciousness, and sleep cycle.

  • Vehicle for sensory information.

  • Made up of the medullary oblongata, pons, and midbrain.

    • Medullary Oblongata: Centre for respiration and circulation; regulates breathing, heart, and blood vessel function.

    • Pons: Links brainstem to spinal cord.

    • Midbrain: Links brain to spinal cord.

• Thalamus

  • Relays motor and sensory signals from the cerebral cortex.

  • Involved in cognition, pain, temperature, pressure, and sensation in general.

• Hypothalamus

  • Controls the autonomic nervous system (ANS) and helps to maintain your internal balance.

  • Regulates heart rate, blood pressure, the pituitary gland, body temperature, appetite, thirst, fluid and electrolyte balance and circadian rhythms.

• Cerebrum

  • The largest part of the brain

  • Responsible for high-level brain functions 

    • Ex. thinking, language, emotion, and motivation

• Cerebellum

  • Top of the brain stem

  • Receives information from the sensory system

  • Responsible for: 

    • Coordinating movements 

    • Regulating balance and posture 

    • Allowing skilled motor activities to be carried out

• Frontal Lobe

  • Directly behind the forehead 

  • Largest lobe in the human brain

  • The most common region of injury

  • Primary Function:

    • Behavior and Emotional Control Centre

  • Important for voluntary movement, expressive language, and managing higher-level executive functions ]→ cognitive skills

  • Controls:

    • Personality/Emotions

    • Intelligence

    • Attention/Concentration

    • Judgment

    • Body movement

    • Problem-solving

    • Speech

  • Damage or injury can cause:

    • Loss of movement (paralysis)

    • Repetition of a single thought

    • Unable to focus on tasks

    • Mood swings/Irritability/Impulsiveness

    • Changes in social behavior and personality

    • Difficulty problem solving

    • Difficulty with language – unable to get words out (aphasia)

• Parietal Lobe

  • Near the back and top of the head

  • Informs about objects in our external environments through touch and the position and movement of body parts.

  • Responsible for integrating sensory input, and the construction of a spatial system to represent the world around us.

  • Controls:

    • Sense of touch, pain, and temperature

    • Distinguishing size, shape, and color

    • Spatial perception

    • Visual perception

  • Damage or injury can cause:

    • Difficulty drawing objects

    • Difficulty distinguishing left from right

    • Spatial disorientation and navigation difficulties

    • Problems reading

    • Lack of awareness of certain body parts or surrounding space

    • Inability to focus visual attention

    • Difficulty with complex movement

• Occipital Lobe

  • At the back of the head

  • Controls:

    • Vision

  • Responsible for visual perception including color, form, and motion.

  • Damage or injury can cause:

    • Difficulty locating objects in the environment

    • Difficulty identifying colors

    • Production of hallucinations

    • Visual illusions – inaccurately seeing objects

    • Word blindness

    • Difficulty reading and writing

• Temporal Lobe

  • Behind the ears and is the second largest lobe

  • Controls:

    • Speech (understanding language)

    • Memory

    • Hearing

    • Sequencing

    • Organization

  • Process auditory information and encode memory.

  • Plays an important role in processing affect/emotions, language, and certain aspects of visual perception.

  • The dominant temporal lobe (left side for most) → helps to understand language. learning and remembering verbal information.

  • The non-dominant → learning and remembering non-verbal information.

  • Damage or injury can cause:

    • Difficulty understanding spoken words

    • Disturbance with selective attention

    • Difficulty identifying and categorizing objects

    • Impaired factual and long-term memory

    • Persistent talking

    • Difficulty recognising faces

    • Increased or decreased interest in sexual behavior

    • Emotional Disturbance

• Limbic Lobe

  • Top of the brain stem and under the cerebral cortex

  • Controls:

    • Emotional processing

    • Behavior

    • Motivation

    • Long term memory

  • It is involved in many emotions and motivations, especially those related to survival.

    • Processing emotions such as fear, anger

    • Emotions related to sexual behavior

Blood Supply

• The brain needs oxygen + nutrients.

• Cerebral Arteries: Posterior supply (basilar artery) in the cerebellum and the anterior supply in the cerebrum.

• Communicating Arteries: Surround the pituitary gland and make up the ‘Circle of Willis’ – this allows the brain to receive blood and nutrients from either the carotid or vertebral arteries.

  • Carotid Artery

    • Internal

      • Origin: Subclavian artery

      • Supply: Blood to the cerebrum.

      • Anterior supply to the brain ascends to three branches and reduces the risk of circulation interruption as there are two supplies.

    • External

      • Origin: Bifurcation of the common carotid artery

      • Branches: Split into 5 arteries e.g., facial artery, occipital artery

      • Supply: Blood to the face, scalp, base of the skull, and neck.

  • Vertebral Artery

    • Origin: Branches of the 1st part of the subclavian artery.

    • Course: Ascends posterior to the internal carotid artery in the transverse foramina of the cervical vertebrae branches.

      • numerous small branches

      • radicular/spinal branches

      • Posterior inferior cerebellar artery (PICA)

    • Termination: Combines with the contralateral vertebral artery to form the basilar artery.

• Blood-Brain Barrier

  • It protects the brain from foreign substances that could injure it.

  • Protects it from hormones and neurotransmitters.

  • Maintains a constant environment for the brain (homeostasis).

  • The highly selective barrier separates circulating blood from the brain’s extracellular fluids in the Central Nervous System.

Energy

• The brain’s main sources of energy are glucose and oxygen → travel from the blood to the brain cells.

• Glucose and oxygen help make ATP within the brain through the process of aerobic respiration.

  • Adenosine triphosphate (ATP): nucleotide which is vital for brain function because it enhances the delivery of nutrients and oxygen to the brain and stimulates the removal of waste products such as glucose and oxygen.

  • Glucose

    • Glucose is a simple carbohydrate that provides fuel for the brain.

    • Glucose travels into the brain cells from the blood through the process of diffusion.

    • The supply of glucose is continuous because carbohydrate storage is limited.

    • The energy from glucose is crucial for communication activity inside the brain, as well as for maintaining memory function.

  • Oxygen

    • Used by the brain to perform its functions.

    • Needed for brain growth and healing.

    • The brain requires 3x as much oxygen as the muscles.  

    • Supplied to the brain cells through the blood via diffusion.

    • Supply is always continuous.

• The effect of low glucose or oxygen levels:

  • Without a constant supply of glucose and oxygen, the brain is unable to function properly. If blood entering the brain is low on either glucose or oxygen, can suffer from:

    • Mental confusion 

    • Dizziness

    • Convulsions

    • Loss of consciousness