HUBS 191: Anatomy Terminology and Homeostasis

• This pre-lecture material helps student prepare for the lecture and helps them take notes during the lecture.
• It's not a substitute for the lecture.
• Differences/additions might occur even though effort is made to ensure this material corresponds to the live lecture.

HUBS 191 Terminology

• Objectives; to explain the concept of homeostasis, explain 'Anatomical Position', define terms used to describe spatial and positional relationships of structures, and define and demonstrate terms of movements as related to joints.
• Terminology is important for effective communication.
• It avoids vague descriptions or directions.
• If you don't know the meaning of words, look them up.
• Consider using Google and add "etymology" to study the origin of words.
• For instance, "Homeostasis" has the components "homeo" meaning "the same" and "stasis" meaning "stopping/staying". Therefore, homeostasis means staying the same.

Homeostasis

• Underpins normal functions of the systems of the human body.
• Maintain conditions in the internal environment.
• Relies on regulatory mechanisms to ensure that controlled variables do not move too far from the set-point which is "normal."
• This includes temperature, ion concentrations (calcium, potassium, sodium), blood sugar levels, and fluid balance and many more.

Homeostasis Feedback and Feedforward

• Feedback occurs when the controlled variable moves too far from the set point, responses from the body attempt to move it back to normal.
• If you get very cold, your body will reduce blood flow to the skin to reduce heat loss, and you might also start shivering to produce heat.
• Feedforward occurs usually when there is an anticipation of an event that will alter a controlled variable, so you may do something to minimize the effect.
• If you see it is snowing, you know that if you go outside in shorts and a t-shirt, your temperature will drop, so you dress in warm clothing before you go outside.
• These concepts will be explored further in HUBS 191 and 192.
• Consider what happens when your body temperature rises and what your body does to correct this increase.
• Also consider what behaviors you consciously do to correct the temperature increase and how the external environment affects your body, and what your response is.

Anatomical Terminology

• Specific terminology is used to refer to body parts, directions, and movements.
• This differs from what you might use in casual conversation.
• Upper limb consists of the: Arm, Forearm, and Hand.
• The lower limb consists of the: Thigh, Leg, and Foot.
• The "Anatomical Position" is Upright, Face Forwards, Feet Together, Palms Face Forwards and remains the same regardless of movement.

Terminology

• Terms of direction describe body parts in relation to other parts, such as:
• Anterior (at the front)
• Posterior (at the back)
• Superior
• Inferior
• Medial
• Lateral
• Proximal
• Distal
• Deep or further from the surface
• Superficial or closer to the surface.
• Skin is superficial to a muscle, and a bone is deep to a muscle.

Division of Body Planes

• The body can be divided into planes.
• Sagittal
• Coronal
• Transverse
• Sagittal divides the body into left and right pieces.
• A midsagittal or median plane divides the body into mirror image left and right halves.
• Coronal divides the body into front and back sections.
• Transverse divides the body into top and bottom sections.

Movements

• Movement occurs in planes; Sagittal which is back and forward movements, Coronal for side to side movements, and Transverse for rotating movements.
• Movement in the sagittal plane is flexion or extension.
• Flexion decreases the angle as fleshy parts of limb brought closer together.
• Extension increases the angle.
• In the Sagittal Plane Dorsiflexion happens when Toes are brought up towards face and Plantarflexion happens when toes are pointing towards ground.
• Movement in the coronal plane involves Abduction and adduction.
• Abduction involves Movement at joint that moves limb away from midline
• Adduction involves movement at joint, moves limb towards midline.
• Inversion happens when the sole of the foot faces towards the midline and eversion happens when the sole of foot turns away from midline.

Movement Types

• Circumduction combines four movements: flexion/abduction/extension/adduction, but NO rotation.
• Rotation is movement around the long axis of a joint either lateral (external) or medial (internal).
• Specialised Movements; Pronation involves palm facing posterior and Supination involves palm facing anterior and forearm bones parallel.

Summary of Main Concepts

• Homeostasis is the maintenance of "normal" set points of bodily functions and its examples will be explored later in HUBS 191 lectures and laboratories
• The anatomical position is a defined reference point for anatomy
• The body can be sectioned in different planes
• Description of anatomical location is usually in relation to another structure for reference
• i.e. nose is superior to chin; thumb is lateral to index finger
• Movement of the body is defined by specific terminology and you will explore these terms in more detail in Laboratories 1 and 2