WK 1 Body organisation

Atoms

Molecules

2 or more atoms working together

Elements

Types of atoms (C, K etc)

Macromolecules

Large, many atoms working together for structure, storage, messengers, and control for biological functions

(e.g. carbs, proteins, lipids/fats, nucleic acids)

Cells

Basic living structural functional unit of the human body to carry out functions that contribute to homeostasis of the body

**Cells no. vary in health and disease

Tissues

A group of similar cells working together. Four primary tissues

• Epithelial - covers + protection, absorption, filtration, excretion/secretion

• Connective - supports

• Muscle - moves specialised for contraction

• Neural - controls + communicates

The structure of the tissue is related to the function

Organs

Structures in the body that consist of 2 or more tissue types working together to perform specific functions essential for maintaining homeostasis.

Organs perform specialized functions to support overall bodily health and processes.

Organ systems

Groups of organs working together to perform complex functions necessary for sustaining life and maintaining homeostasis.

They control, direct, cool/warm, digest, move, protect, remove, reproduce, store, support, transpor

Body cavities

Spaces withing the body that enclose internal organs. These spaces are separated by bones, muscles, ligaments and membranes.

Function - they act to protect the body from shocks and impacts as they can change shape (expand/contract) to move without impending function

2 major ones 1) Thoracic 2) Abdominal pelvic

Anatomy

Means ‘cutting open’. It is the scientific study of the body’s structures. Some body structures are very small and can only be observed with a microscope (like our cells), while others are large enough to be observed with the naked eye (e.g., bones and muscles).

Anatomy is the STRUCTURE. When we study anatomy, we are asking questions like What does it look like? Where is it? What structures are nearby? and What structures is it connected to?

Physiology 

Physiology is the study of how the body works; the function of body parts and how they work together to maintain life. Much of the study of physiology centres on the body’s tendency toward homeostasis. Physiologists may work from the molecular level (such as exploring how electrochemical signals travel along nerves) to the organ level (exploring, for example, what different parts of the brain do).

Physiology is the FUNCTION. When we study physiology, we are asking questions like ‘What does it do?’ and ‘How does it work?’

Histology 

Study of biological cells and tissues

For example, using microscopy to determine the specific cells that comprose an individual muscle, or visualise which epoithelial cell is lining the respiratory tract. 

Anatomical position 

What is it?

Standing erect Head level and eyes facing forward Hands at side and palms forward Legs parallel, feet flat on the floor.

Why is it important?

Descriptions of any region or part of the human body assume that it is in a standard position of reference.  The anatomical position provides a common world-wide reference point for describing the location of body parts and regions.

Supine

What is it?

The body is in a horizontal position with the face and upper body orientated upwards.

Why is it important?

One of two terms that describe a reclining body; each of which are used in different medical circumstances. This is the most common position for surgery, particularly when access to the thoracic cavity is required. Supine is the typical starting position for human dissection and autopsies.

Prone

What is it?

The body is in a horizontal position with the face and upper body orientated downwards.

Why is it important?

One of two terms that describe a reclining body; each of which are used in different medical circumstances. Some surgical procedures require a prone position, particularly when access to the posterior spine, buttocks or perirectal area is required. The prone position helps increase oxygenation in patients with respiratory distress.

Ionic bond

Form when one or more electrons are transferred from one atom to another. This creates + cation and - anion, being oppositely charged they are attracted to each other through strong electrostatic forces creating a chemical bond

• High melting points

• Can dissociate

• Most are soluble in water

Covalent bonds

When 2x atoms share a pair of valence electrons

Organic compounds

All contain elements of living things carbon and hydrogen (e.g. carbs, lipids, proteins, nucleic acids)

Inorganic compounds

Not made of living things (generally don’t have C or H)

e.g. CO2, H2O, salts

pH

A scale that measures H+ concentration to be acidic or alkaline 0-14, 7 = neutral

Bases: Can react with acids to neutralise

Alkasis: Dissolve in water

Plasma membrane

Selectively permeable membrane made of a phospholipid bilayer that maintains the composition of ICF + ECF

It determines the movement of substance in or out and communicates with other cells and organs, and links adjacent cells

Membranes of the body

Physical barriers that line parts of the body, consisting of epithelium + supports connective tissue

i.e.

• Mucous - line digestive, respiratory, urinary, reproductive

• Serous (Pleural, Pericardia) - live body cavities

• Cutaneous - skin bodies surface

• Synovial - line joint cavities + produce fluid within

Simple diffusion

[high] - [low]

Unassisted, lipid soluble, small, uncharged

Facilitated diffusion

[high] - [low]

Passive transport, uses assistance of specific transmembrane proteins (carrier proteins)

Used because substance is too polar (charged) to move through membrane

Osmosis

[High H2O] - [Low H2O] i.e. low solute to high solute

Moves through an aquaporin is passive aiming to equalise solute concentration on both side of the membrane

hypotonic /hypertonic

Active transport

[low] - [high] goes against the gradient

energy expenditure (mostly ATP)

Passive transport

Random motion + collisions of ions (kinetic energy)

Tonicity

*****

Isotonic

(normal)

No net gain or loss - therefore retains shape

Hyertonic

(crenation)

• Higher concentration of solutes compared with what’s in the cells

• Cell loses water via osmosis

• Shrivels = cell dehydration

Hypotonic

(haemolysis/ swelling)

Lower concentration of solutes outside the cell

Homeostasis

The bodies ability to maintain a constant state of equilibrium

Feedback systems

Cycle of events in which the body conditions are

• Monitored

• Evaluated

• Maintained or changed

• Re-evaluated

Components

Controlled condition - variable that’s maintained

Stimulus - any disruption to controlled condition

Receptor - detects the change + notifies control centre

Control centre - sets range, receives information, evaluates + processes information sends output commands to effector

Effector - receives commands from control centre + produce response

Response - effect that changes the controlled condition

Negative feedback

The response opposes the initial stimulus to reverse the change

• Most common for homeostatic mechanisms

• For conditions needing frequent adjustments

  e.g. body temp, BP, BGL, BpH

Positive feedback

The response strengthens or enhances the stimulus to produce an even greater response (amplified change)

• When rapid change is needed

  e.g. oxytocin during childbirth, platetet plug in blood clotting