Biology

The Human Excretory System maintains homeostasis by regulating body fluid volume, ion concentration, pH, and elimination of metabolic wastes.

1. Parts:

• a pair of kidneys
• a pair of ureters
• a urinary bladder
• a urethra

2. The kidney:

• dark purplish – immense blood supply
• shaped like a bean
• located at both sides of the vertebral column
• in the back of the abdominal cavity
• easily detached
• held in position by connective tissue and protected by a ...

In the thoracic cavity, lies between the lungs, behind the breast bone

Structure

• fist-sized

• layers:

• pericardium – tough protective sac
• heart muscle - myocardium
• endocardium -> valves

• cardiac muscle :

never gets tired (doesn’t fatigue)

striated muscle

involuntary

cells branch

thickest in left ventricle’s wall

• ...

A bout 5 litres

pH 7.4

Function:

• Transports
  • respiratory gases
  • nutrients
  • waste materials
  • hormones
  • enzymes
• regulates
  • body temperature
  • pH
• protects against
  • blood loss
  • foreign agents

Blood components:

Respiration : process by which living organisms exchange gases with their environment.

Subprocesses:

• Ventilation: exchange of air into the respiratory organ
  • Inhalation
  • exhalation

• External respiration : gas exchange between air and blood by diffusion

• internal respiration: gas exchange between blood and tissues, cells

• cellular respiration: biological oxidation

Learn more about the human body's respiratory system.

The ...

The alimentary canal has 3 parts:

• Foregut : oral cavity, pharynx, esophagus, stomach
• Midgut: small intestine
• Hindgut: large intestine – caecum, colon, rectum

Humans are heterotrophic omnivores. -> gut processes many kinds of food

Enzymes:

• cleave the chemical bonds of macromolecules through addition of water (hydrolysis)

-> hydrolytic enzymes

• classified according to substrate
  • protease, peptidase
  • carbohydrase (maltase, lactase, ...

Nutrition: The process by which living organisms obtain food necessary for metabolism.

The stages of nutrition are ingestion of nutrients, digestion, absorption and the elimination of wastes.

• Nutrient: materials needed to maintain life functions
• Nutriment (food) = nutrients + indigestible wastes

  Nutrients

1. proteins
2. carbohydrates
3. fats (lipids)
4. fibres
5. vitamins –small organic molecules, which the body cannot synthesize, only from pro-vitamins -> ...

Skeletal muscles:

• make up nearly half the body weight of an adult
• contraction: need E + O2 -> rich blood supply
• functions: active movement, heat generation, stores glycogen

Structure:

• cells = muscle fibres:
  • long, have many nuclei
  • contain myofibrils – contractile elements
    • actin – thin
    • myosin – thick

      

  • gives a striped appearance à striated muscle
  • we can move them at will à voluntary muscle
• muscle fibres form bundles ...

I. Types of bones

a) long bones

E.g.: femur, tibia, fibula, humerus, radius, ulna

b) flat bones

E.g.:  scapula                                                    bones of the skull

II. Structure of bones

• cartilage
  • at the end of long bones
• compact bone :
  • concentric rings (lamellae)
  • with central canals
  ...

Human Locomotion System

Main parts of the human locomotion system:

• skeletal system (bony endoskeleton)  -> passive
•  muscular system (skeletal muscles) -> active

Functions of vertebrate skeleton:

• supports – framework for the body
• movement – skeletal muscles attach to it
• protects internal organs(brain, heart, lungs)
• stores minerals: calcium, phosphate
• produces blood cells

The skeletal system

206 bones (270 at birth – fusing ...

My power point presentation about the structure and function of the skin

50 incredible facts about your skin 

Quizlet flashcards about the human skin

Learningapps labelling task

Learningapps matching task - Which layer of the skin do these statements refer to? 

Experiments with your skin.

Station 1: Locating Sweat Glands

There are more than 2 million pores that produce sweat on your skin. Sweat glands are very difficult to locate with the human eye, but this activity ...