Cell Specialisation and Body Systems Overview

Cell Specialisation

The process where cells develop distinct structures and functions suited to specific roles.

Organisation of Specialised Cells

Specialised cells → Tissues → Organs → Systems → Organism.

Digestive System Function

To break down food into absorbable nutrients and eliminate undigested waste.

Mouth Function

Mechanical digestion, salivary enzymes.

Esophagus Function

Transports food via peristalsis.

Stomach Function

Churns food, secretes acid and enzymes.

Small Intestine Function

Absorbs nutrients via villi.

Liver Function

Produces bile for fat digestion.

Pancreas Function

Secretes enzymes and bicarbonate.

Large Intestine Function

Absorbs water, forms feces.

Rectum/Anus Function

Stores and expels feces.

Digestive System Homeostasis

By providing nutrients and water necessary for cellular functions and energy balance.

Endocrine System Function

Regulation of body processes through hormone secretion into the bloodstream.

Hypothalamus Function

Controls pituitary.

Pituitary Gland Hormones

GH, TSH, ACTH.

Thyroid Hormone

Thyroxine (metabolism).

Pancreas Hormones

Insulin, glucagon.

Adrenal Gland Hormones

Adrenaline, cortisol.

Ovaries/Testes Hormones

Estrogen, testosterone.

Endocrine System Homeostasis

Hormones adjust physiological functions such as glucose levels, metabolism, and water balance.

Excretory System Function

To remove metabolic waste and regulate fluid, salt, and pH balance.

Kidneys Function

Filter blood, produce urine.

Ureters Function

Carry urine to bladder.

Bladder Function

Stores urine.

Urethra Function

Excretes urine.

Skin Function in Excretion

Removes water, salts, urea.

Lungs Function in Excretion

Excrete carbon dioxide.

Kidneys Water and Salt Regulation

Via filtration and reabsorption in nephrons, influenced by ADH.

Homeostasis

The maintenance of a stable internal environment despite external changes.

Feedback Loop

A biological mechanism where changes trigger responses that restore balance.

Negative Feedback

Reverses change (e.g., glucose control).

Positive Feedback

Enhances change (e.g., childbirth).

Body Temperature Regulation

Hypothalamus controls responses like sweating (cooling) or shivering (warming).

Blood Glucose Regulation

High glucose → insulin → cells/liver absorb glucose. Low glucose → glucagon → liver releases glucose.

Water Balance Maintenance

ADH controls kidney reabsorption of water depending on hydration levels.

Type 1 Diabetes Cause

Autoimmune destruction of pancreatic β-cells → no insulin production.

Symptoms of Untreated Type 1 Diabetes

Thirst, fatigue, weight loss, blurred vision, long-term organ damage.

Hypoglycaemia

Low blood glucose; symptoms include confusion, shakiness. Treated with quick sugar intake.

Hyperthyroidism

Excessive thyroxine production → rapid metabolism, weight loss, anxiety, increased heart rate.

Consequences of Homeostatic Failure

Disruption of body function, risk of coma, organ failure, or death.

Systems Involved in Type 1 Diabetes Case

Endocrine (insulin), muscular (activity), circulatory (glucose transport).

Exercise Effect on Glucose Levels

Muscle activity increases glucose use; without insulin control, this can cause hypoglycaemia.

Main Risks for Student with Type 1 Diabetes

Blood sugar crashes during or after activity, risk of fainting or seizures.

Strategies to Manage Type 1 Diabetes

Glucose monitoring, adjusted insulin doses, planned snacks, emergency response training.