Male

What is sexual reproduction

• organisms produce offspring through the union of gametes

What is gametogenesis

• the production of gametes

  • spermatogenesis

  • oogenesis

What is a gamete

• germ cell with haploid number of chromosomes

  • sperm cells

  • secondary oocytes

What are gonads

• produce gametes and secrete hormones

What are ducts

receive, transport and store gametes

What do accessory sex glands and organs produce

produce materials that support gametes

What are perineal structures known as

external genitalia

What 2 things do testes secrete

• secrete sex hormones

  • androgens

• secrete mature spermatozoa

How is semen formed and expelled

• mature spermatozoa travels though duct system

• mix with secretions off accessory glands (semen)

• semen expelled via ejaculation

What are the 2 functions of the testes

• produce sperm

• secrete hormones

What is the function of the ductal system

• sperm maturation

What is the function of the accessory sex glands

• add secretions to semen

What is the function of the penis and scrotum as supporting structures

• support for testes and sperm delivery

Where does spermatogenesis occur

seminiferous tubule

What 2 cells do seminiferous tubules contain

• spermatogenic cells

  • at various development stages

• sertoli cells

  • nurse cells

What is the function and location of leydig cells

secrete testosterone between seminiferous tubules

What is the process of spermatogenesis

• seminiferous tubules produce sperm

• takes 65-75 days

• start at outermost layer of cell and towards lumen

What are the 3 stages of spermatogenesis

• mitosis

  • spermatogonia proliferation

• meiosis

  • primary and secondary spermatocytes and spermatids

• spermiogenesis

  • transformation of spermatids to mature spermatozoa

What are spermatids

small unspecialised cells

What is spermiogenesis

spermatids mature to spermatozoa

What is the 6-step process of spermiogenesis

• nucleus condenses and elongates

• acrosome forms

• mitochondria multiply and organise into neck

• flagellum develops

• loss of cytoplasm

• sertoli cells get rid of excess

What is the structure of a sperm

• head

  • chromosome and acrosome cap

• middle

  • mitochondria → ATP

• tail

• lacks organelles

  • reduced size and weight

What are sertoli (nurse) cells

• extend from basement membrane to lumen

• nourish spermatocytes, spermatids and sperm

• have testosterone and FSH receptors

• phagocytosis of cytoplasm sheds spermatid

• produce fluid for sperm transport

What happens when inhibin is secreted

• regulates rate of sperm production

  • negative feedback loops

What is spermiation

• spermatozoon loses attachment to nurse cell

  • enters lumen of seminiferous tubule

• fluid secreted by sertoli cells

  • pushes sperm towards ducts of testes

What is epididymis

• sperm maturation

  • 14 days

• can store sperm for several months

• tail of epididymid continues as ductus deferens

What is ductus deferens

• converts sperm during sexual arousal

• can store sperm several months

What is semen and its 3 functions

• mixture of spermatozoa and accessory sex gland secretion

  • provide the fluid that transports spermatozoa

  • provides nutrients

  • neutralises acidity

What is the composition of semen

• spermatozoa

• seminal fluid

  • nurse cells

  • seminal glands

  • prostatic fluid

  • bulbo-urethral glands

What 3 things are secreted by seminal glands

• fructose

  • ATP

• prostaglandins

  • sperm motility

• clotting proteins

  • semenogelin

What does the prostrate gland secrete

• milky, slightly acidic fluid

  • citric acid (ATP production)

  • proteolytic enzymes

What is the bulbo-urethral gland and what does it secrete

• pea sized glands

• active during sexual arousal

• secrete sticky mucus

  • lubrication

• alkaline fluid

What is the urethra

• shared terminal ducts

  • passageway for semen and urine