SEMI-FINALS REVIEW on HUMAN BODY SYSTEMSPrepared by: Earshad B. BanjalNatural Science DepartmentCollege of Arts & Sciences EducationUniversity of Mindanao, Matina, Davao City

THE EXCRETORY SYSTEM

excretes METABOLIC WASTES (urea, excess water & minerals) from the body

PRINCIPAL ORGANS:

1. KIDNEY – water, urea &

other metbolic wastes

2. LUNGS – water vapor &

carbon dioxide

3. LIVER – urea

4. SKIN – water, salt, urea

NEPHRON – functional unit of KIDNEYS

HOW IS URINE PROCESSED & EXCRETED?

1. Blood enters through Glomerulus, which is covered by the Bowman’s capsule, where FILTRATION happens.

2. Salt, urea, ions, and dissolved substances (all called filtrate) move through the tubules (proximal, Loop of Henle, & distal).

3. REABSORPTION, or the reabsorption of important substances like water & salt, happens mostly in the Loop of Henle.

HOW IS URINE PROCESSED & EXCRETED? (cont.)

4. The filtrate with substances that were not reabsorbed enters the collecting duct, in the process of URINE EXCRETION.

5. This filtrate is now called urine, and will now flow to the ureters.

TRACE THE PATH OF URINE FLOW.

1. From the COLLECTING DUCT, urine flows through the URETER.

2. URETER empties urine into the URINARY BLADDER.

3. URINARY BLADDER temporarily stores urine, until it is excreted through the URETHRA.

THE NERVOUS SYSTEM

collects information about the body’s

internal & external environment, processes

that information, & responds to it

DIVISIONS OF THE NERVOUS SYSTEM:

1. Central Nervous System – the brain & spinal cord

2. Peripheral Nervous System – the nerves

NEURON – the basic unit (cell) of the Nervous System

Neurons transmits IMPULSE,

or electrical signals.

DENDRITES receives, AXON

transmits the signals to other neurons.

THREE TYPES OF NEURONS:

1. SENSORY – collects stimulus

from the outside

2. INTERNEURON – transmits

impulse to other neurons, to

the spinal cord, or brain

NEURON transmits chemical signals, or NEUROTRANSMITTERSTHREE TYPES OF NEURONS:

3. MOTOR NEURONS – carries

signals to the effectors, or

target organs

HOW ARE SIGNALS GENERATED?

When stimulus is transformed

into impulse in dendrites, the signal

travels along the axon. As it reaches

the synapse, the axon releases

neurotransmitters.

THE CENTRAL NERVOUS SYSTEM

DIVISIONS OF THE BRAIN:

1. Cerebrum – largest; voluntary activities, intelligence, learning, judgment

a) HEMISPHERES: Left – logic, analytic, reasoning; Right – arts, passion, creativity

2. Cerebellum – “little brain”; involuntary, balance & coordination

THE CENTRAL NERVOUS SYSTEM (CNS)

DIVISIONS OF THE BRAIN:

3. Brain Stem – connects the brain & spinal cord; involuntary; life-sustaining activities, breathing, heart rate, BP, swallowing

a) Midbrain

b) Pons

c) Medulla Oblongata

THE PERIPHERAL NERVOUS SYSTEM (PNS)

Transmits signals to the brain through the spinal cord & receives signals from the brain that enervates the effectors.

DIVISIONS OF THE PNS:

1. Sensory Division – from sense organs to CNS

2. Motor Division – from the CNS to muscles or glands (all called effectors)

a) SOMATIC NERVOUS SYSTEM: voluntaryb) AUTONOMIC NERVOUS SYSTEM: involuntary

i. SYMPATHETIC - stimulatesii. PARASYMPATHETIC - relaxes

THE SKELETAL SYSTEM

supports the body; protects internal organs; stores minerals; site of blood formation

DIVISIONS OF THE SKELETAL SYSTEM:

1. Axial – central axis includes skull, vertebrae, & ribcage

2. Appendicular – arms & legs

OSCTEOCYTE – basic unit (cell) of the Skeletal System

HAVERSIAN CANAL provides pathway for nerves & vessels to the osteocytes.

BASIC STRUCTURE:

1. Epiphysis – end part; covered w/ cartilage

2. Diaphysis – long body part

3. Periosteum – covers the bone

4. Marrow – storage for fats; site of blood cell formation

OSSIFICATION – bone formation

Joints – hold bones together

1. Diarthroces – allows movement

2. Synarthroces – do not allow movement, example: suture joint in the skull

LIGAMENTS connects skeletal muscles to the bones.

TYPES OF SKELETAL SYSTEM

3. Exoskeleton – external; insects and other animals

4. Endoskeleton – inside: humans and animals

OSTEOPOROSIS – bone degradation

THE MUSCULAR SYSTEM

THREE TYPES OF MUSCLE TISSUE:

1. Skeletal Muscle – connected to the bones; voluntary; striated (banded): biceps, calf muscles, abs

2. Smooth Muscle – forms the structure of some internal organs; involuntary; unstriated: urinary bladder, stomach, intestine

3. Cardiac Muscle – involuntary; striated: heart only

MYOFIBER – a bundle of muscle, composed of myofibrils

HOW DO MUSCLES CONTRACT?

Each MYOFIBRIL is composed of ACTIN & MYOSIN filaments. Muscle will contract if actin & myosin are attached to each other (called CROSS-BRIDGE). If not, muscles are relaxed.

Muscles work in pairs. Muscle pairs are ANTAGONISTIC, meaning they work oppositely. Example: when biceps contract, triceps relax; vice-versa.

SARCOMERE – single length of actin & myosin, bounded by Z-disc

THE INTEGUMENTARY SYSTEM

barrier against infection & injury; regulates body temperature; removes wastes from the body; gathers information; produces vitamin D

PRIMARY STRUCTURES:

1. Skin – major organ of the integumentary system

2. Hair – composed of keratin; protects us from UV; prevent dirt from entering the body; insulation from cold

3. Nail – composed of keratin

MELANOCYTES – skin cells, producing melanin (brown pigment)

LAYERS OF SKIN:

1. EPIDERMIS – outermost layer; contain MELANOCYTES; produces keratin

2. DERMIS – contains collagen, nerves, vessels, glands, smooth muscles, hair follicles; SEBACEOUS GLANDS – produce oil

3. HYPODERMIS (SUBCUTANEOUS LAYER) – fats (adipose tissue)

THE RESPIRATORY SYSTEM

picks up oxygen from INSPIRATION (inhalation) & releases carbon dioxide in EXPIRATION (exhalation)

PRIMARY STRUCTURES:

1. Nose – warms & moistens the air; traps dirt

2. Pharynx (throat) – passageway for both air & food

3. Epiglottis – prevents the entrance of food to trachea

4. Larynx – voice box

BREATHING relies on simple DIFFUSION of gases

5. Trachea – cartilaginous; traps and sweeps out dirt through CILIA

6. Bronchi & bronchioles – branch off to each lung

7. Alveoli – grape-like structures where gas exchange occurs

8. Lungs – two structures that house the bronchi & alveoli, and other related structures

9. Diaphragm – dome-shaped muscle beneath the lungs

TRACE THE PATHWAY OF AIR IN & OUT OF THE RESPIRATORY SYSTEM

BREATHING MECHANISM

During inspiration:

Rib cage rises; Diaphragm contracts (lowers); Air pressure decreases; Volume increases

During expiration:

Rib cage lowers; Diaphragm relaxes (rises); Air pressure increases; Volume decreases

THE ENDOCRINE SYSTEM

delivers chemical messages (hormones) throughout the body

hormones are released by the endocrine glands to target organs or substances

GLANDS:

1. Exocrine glands – with ducts (vessel) pouring into external environment or the digestive system

2. Endocrine glands – ductless, pour its contents directly into the blood

PITUITARY GLAND – the master gland of the Endocrine System

(Please refer to your book for the complete list of hormones, Introduction to Biology by Aldea, et al., pages 116-117)

NEGATIVE FEEDBACK SYSTEM – regulates the secretion of the endocrine glands by inhibiting the glands themselves if there is an excess of the substance to be controlled; or activating the glands if there is a deficiency of the substance to be controlled

EXAMPLES OF ENDOCRINE-RELATED DISORDER

1. Diabetes Mellitus – inactive pancreas, deficiency in insulin production

2. Cretenism (hypothyrodism) – small stature; low metabolism, lack energy

3. Pituitary dwarfism – small stature, short appendages, underdeveloped body parts

4. Gigantism - “giant” physical stature from overproduction of Growth Hormone

5. Goiter – enlarged thyroid gland, less production of thyroxine because of decreased consumption of Iodine-rich food

THE REPRODUCTIVE SYSTEM

Sexual development in both male and female starts at the onset of PUBERTY, when the hypothalamus signals the pituitary glands to produce Follicle-stimulating Hormone (FSH) and Luteinizing Hormone (LH).

FSH & LH affect the gonads (testis & ovaries).

In males, LH stimulates production of TESTOSTERONE; FSH stimulates the development of sperm cells.

In females, FSH stimulate the ovaries to produce ESTROGEN, to start producing egg. LH functions in menstrual cycle.

THE MALE REPRODUCTIVE SYSTEM

PRIMARY STRUCTURES:

1. Testes (testis pl.) – produces the sperm cells in the SEMINIFEROUS TUBULES

2. Epididymis – where sperm matures

3. Vas Deferens – tube that connects the epididymis to urethra; pathway of SEMEN (sperm + seminal fluid = semen) during EJACULATION

4. ACCESSORY GLANDS: Seminal Vesicle, Prostate Gland, & Bulbourethral Gland (Cowper’s Gland) – produce SEMINAL FLUID

5. Urethra – pathway for both semen & urine

One drop of semen = 2.5 million

SPERM STRUCTURE:

1. Head – houses the nucleus & acrosome (organelle that punctures the covering of the egg)

2. Midpiece – mitochondria-laden

3. Tail or Flagellum – for movement

LET’S TAKE A CLOSER LOOK!

THE FEMALE REPRODUCTIVE SYSTEM

PRIMARY STRUCTURES:

1. Ovary – produces the ovum (egg)

2. Fallopian Tube (Oviduct) – where the egg is released into & fertilization occurs

3. Uterus (womb)– houses the embryo

4. Cervix – opening of the uterus

5. Vagina – receives the penis during sexual intercourse

THE MENSTRUAL CYCLE

Happens every 28 days in the average

PHASES OF THE MENSTRUAL CYCLE

1. Follicular Phase – FSH & LH rise, cause the follicle (egg cell plus the surrounding cells) to mature; estrogen rises causing the walls of the uterus to thicken

2. Ovulation – release of egg into the oviduct, leaving the follicle in the ovary

3. Luteal – the follicle turns yellow (CORPUS LUTEUM) ; LH & FSH lower, progesterone is released to further thicken the uterine wall

4. Menstruation – last about 3-7 days; because of low estrogen, blood is shed with the ovum in it

FERTILIZATION & DEVELOPMENT

During sexual intercourse, millions

of sperm are released in the female

reproductive tract.

Only one sperm (usually) fertilizes an egg.

A ZYGOTE is formed in fertilization.

In case of multiple embryos, twins can develop either when: a zygote divides further into two embryo, or 2 sperm cells & 2 egg cells are simultaneously fertilized.

FERTILIZATION happens in the fallopian tube.

MARAMING SALAMAT PO SA PAKIKINIG.

DISCLAIMER

Dear Class (BE 305, 306, 327),

This will serve as a SUPPLEMENT for your review for the semi-final exam. The best thing for you to do is study your book, lecture notes, prior quizzes & the reports of your classmates. Please be guided accordingly to further instructions that I will post on Facebook on or before Monday, July 28.

Yours truly,

Your Handsome Teacher =)