Ch 07: Control, Coordination & Movement

⚡ Nervous System — Overview

Coordination = Balance between external/food reactions + maintaining normal conditions
Nervous system provides control via electrical impulses
Neuron: Structural and functional unit
Synapse: Junction between two neurons — transmits electrical impulses

Impulse path:Stimulus → Receptor → Sensory neuron → Brain/Spinal cord → Motor neuron → Effector organ

📋 Human Nervous System — Divisions

CNS (Central)

Brain (1300–1400 gm)
Forebrain, Midbrain, Hindbrain
Spinal cord

PNS (Peripheral)

Cranial nerves: 12 pairs
Spinal nerves: 31 pairs

ANS (Autonomic)

Sympathetic NS
Parasympathetic NS

⚡ Quick Recall

Reflex action = Automatic, involuntary response to stimulus. A simple spinal reflex is integrated in the spinal cord; the brainstem also controls protective reflexes.

👁️ Receptors

Organ	Sensation
Ear	Hearing + Maintains body balance
Eye	Vision
Skin	Touch, Heat, Pain perception
Nose	Smell receptors
Tongue	Taste buds / receptors

⚡ Quick Recall — Eye Facts

Iris: Controls pupil expansion/contraction | Cornea: Transparent front part | Lacrimal gland: Releases tears | Superior rectus: Eye muscle controlling eye movements

⚠ Exam Trap

Simple spinal reflexes are integrated in the spinal cord; some protective reflexes involve the brainstem. The eardrum behaves like a rubber sheet. Endocrine system = Chemical coordination (hormones). Nervous system = Electrical coordination (impulses).

🧠 Brain — Parts & Functions

1300–1400 gm

Brain weight

Forebrain

Voluntary actions

Midbrain

Vision & hearing reflexes

Hindbrain

Brain ↔ Spinal cord

1️⃣ Forebrain

Olfactory Lobe

Sense of smell

Cerebrum

Memory, Consciousness
Reasoning, Learning
Amnesia: Memory loss
Dementia / Alzheimer's: Memory loss + daily activity problems

Diencephalon

Thalamus: relay and processing of most sensory impulses before they reach the cerebral cortex
Hypothalamus: Appetite, thirst, affection, disgust, sleep, heat control

2️⃣ Midbrain

Aids in vision and hearing reflexes
Changes in pupil size
Control of involuntary actions

3️⃣ Hindbrain

Connects brain and spinal cord

Pons

Respiratory center

Cerebellum

Maintains muscular balance
Controls posture

Medulla Oblongata

Breathing rhythm
Heart rate
Hiccups
Controls ANS

⚠ Exam Trap

Cerebellum = Balance & Posture (NOT memory). Cerebrum = Memory, reasoning. Medulla oblongata = Breathing + Heart rate. Hypothalamus = Appetite, thirst, sleep. These are four distinct functions.

⚡ Quick Recall

Alzheimer's / Schizophrenia → affects emotions and behaviour. Spinal cord → integrates spinal reflexes; the medulla participates in protective reflexes.

💉 Endocrine System — Overview

Hormones coordinate body activities through endocrine glands
Secreted by ductless endocrine glands in small quantities
Act as chemical messengers regulating body functions
Types: Peptides or Steroid

📋 Major Hormones — Complete Table

Gland	Hormone	Function	Hyposecretion Effect
Pituitary (Anterior)	Somatotropic / Growth Hormone (GH)	Control body growth	Pituitary dwarfism, stunted growth in childhood
Thyroid Gland	Thyroxine	Controls all basal metabolic activities (BMR)	Cretinism (children), Goitre (swelling in throat)
Adrenal Gland (medulla / cortex)	Adrenaline / Epinephrine (do/die hormone), Nor-adrenaline	Increase BP, heartbeat; controls blood pressure	Addison's disease: underproduction of adrenal-cortex hormones, distinct from medullary adrenaline
Pancreas (β-cells)	Insulin	Lowers blood sugar	Diabetes, excess water in urine
Pancreas (α-cells)	Glucagon	Raises blood sugar	Hypoglycemia
Testes (Men)	Testosterone (Androgen)	Secondary sexual characters, Spermatogenesis	Impotence
Ovaries (Women)	Oestrogen, Progesterone	Secondary sexual characters, Oogenesis, Prepare uterus for pregnancy	Infertility

⚠ Exam Trap

Insulin = β-cells of Islets of Langerhans (LOWERS blood sugar). Glucagon = α-cells (RAISES blood sugar). Both hormones are secreted by the pancreas, but by different types of cells. Adrenaline = "Do or Die hormone".

⚡ Quick Recall

Goitre = Thyroid (iodine deficiency → Thyroxine deficiency). Cretinism = Thyroid in children. Dwarfism = Pituitary (GH deficiency). Diabetes = Pancreas (Insulin deficiency).

💪 Muscular System

Feature	Striated (Skeletal)	Unstriated (Smooth)	Cardiac
Type	Voluntary, Skeletal	Involuntary, Smooth	Involuntary, Striated
Bands	Alternating actin & myosin bands	No bands	Bands present
Location	Attached to skeleton	Uterus, Intestines, Pupil of eye, Trachea	Heart

Strongest muscle:Masseter (jaw) Largest muscle:Gluteus maximus

⚠ Exam Trap

Strongest muscle = Masseter (jaw). Largest muscle = Gluteus maximus. Cardiac = striated but involuntary!

🦴 Human Skeletal System — Total 206 Bones

Body Part	Section	Bones (Name & Count)
Head	Skull (Cranium)	Occipital(1), Parietal(2), Frontal(1), Temporal(2), Sphenoid(1), Ethmoid(1) = 8
	Face	Nasal(2), Vomer(1), Inf. nasal conchae(2), Lacrimal(2), Palatine(2), Zygomatic(2), Maxilla(2), Mandible(1) = 14
	Ear bones	Malleus(2), Incus(2), Stapes(2) = 6
	Hyoid	Hyoid(1) = 1
Vertebral Column	Neck (Cervical)	7
	Chest (Thoracic)	12
	Waist (Lumbar)	5
	Sacrum	1 (5 in infants)
	Coccyx	1 (4 in infants)
Thorax	Sternum + Ribs	Sternum(1) + Ribs(24) = 25
Girdles & Upper Limbs	Pectoral girdle	Scapula(2) + Clavicle(2) = 4
	Pelvic girdle	Innominate(2) = 2
	Upper arm	Humerus(2) = 2
	Lower arm	Radius(2) + Ulna(2) = 4
	Wrist (Carpal)	16
	Palm + Fingers	Metacarpals(10) + Phalanges(28) = 38
Lower Limbs	Thigh (Femur)	Femur(2) = 2 (Largest & strongest bone)
	Shin	Tibia(2) + Fibula(2) = 4
	Knee (Patella)	2
	Ankle + Sole	Tarsal(14) + Metatarsals(10) = 24
	Toes (Phalanges)	28
TOTAL		206 Bones

⚠ Exam Trap

Total bones = 206. Largest & strongest bone = Femur (thigh). Cervical vertebrae = 7 (neck). Ear bones: Malleus, Incus, Stapes (smallest bone in body!). Ribs = 24 (12 pairs).

⚡ Quick Recall — Vertebrae Formula

Cervical 7 · Thoracic 12 · Lumbar 5 · Sacrum 1 · Coccyx 1 = 26 vertebrae total

🔗 Types of Joints

Joint Type	Mobility	Location / Example
Immovable	No movement	Skull bones; Teeth & jaw joint
Semi-movable	Limited movement	Pubic symphysis (pelvic girdle)
Ball & Socket	All-direction movement	Shoulder and hip
Hinge	One-direction (like door hinge)	Elbow, Fingertips
Pivotal	Rotation	Atlas & Axis (neck)
Saddle	Two-direction movement	Base of thumb (trapezium–first metacarpal)

⚡ Quick Recall

Movable joints contain Synovial fluid in the synovial cavity — provides lubrication. Ball & socket = maximum movement (shoulder). Hinge = only flex/extend (elbow).

⚠ Exam Trap

Skull joints = Immovable. Neck (Atlas-Axis) = Pivotal. Elbow = Hinge. Shoulder = Ball & Socket. These four examples are frequently tested.

🌿 Plant Movements

Tropic Movement (Growth-related)

Movement in direction of stimulus or opposite
Phototropism: Response to light
Root = negative (away from light) | e.g. Sunflower
Geotropism: Response to gravity
Roots = positive (towards gravity) | Shoot = negative
Hydrotropism: Movement towards water
Chemotropism: Response to chemical
e.g. Pollen tube growth towards ovule in style

Nastic Movement (Direction-independent)

May involve turgor changes or growth, depending on the type
Unaffected by direction of stimuli
e.g. Touch-me-not plant (Mimosa pudica)

⚠ Exam Trap

Tropic = Growth-related, direction matters. Nastic = Direction-independent; may involve turgor changes or growth. Touch-me-not = Nastic (thigmonasty). Sunflower = Phototropism.

🌱 Plant Hormones

Category	Hormone	Key Functions
Growth Promoters	Auxin	Apical dominance, Cell elongation, Parthenocarpy (fruit formation without fertilisation)
	Gibberellin	Stem/internode elongation, Bolting, Seed germination
	Cytokinin	Cell division, Delays senescence, Breaks dormancy
Growth Inhibitors	Abscisic Acid (ABA)	Closing of stomata (stress), Dormancy, Senescence
Growth Inhibitors	Ethylene (Gaseous hormone)	Ripening of fruits, Senescence

⚠ Exam Trap

Ethylene = only gaseous plant hormone → fruit ripening. ABA = "Stress hormone" of plants → stomata close, dormancy. Auxin = Apical dominance (tip suppress side branches). Gibberellin = Bolting (rapid stem elongation).

⚡ Quick Recall

Growth Promoters: Auxin · Gibberellin · Cytokinin → AGC
Growth Inhibitors: ABA · Ethylene

🧠 Chapter 07 — Control, Coordination & Movement